diff --git a/CHANGES.md b/CHANGES.md
index bbd253bfe81..edb319d2769 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -11,6 +11,8 @@ To be released.
  -  `Peer.AppProtocolVersion` became nullable to represent `Peer` whose version
     is unknown.
  -  Added `IStore.ListAddresses()` method.  [[#272], [#285]]
+ -  Renamed `BlockChain<T>.GetNonce()` method to `BlockChain<T>.GetNextTxNonce()`
+    method.  [[#294]]
 
 ### Added interfaces
 
@@ -22,6 +24,8 @@ To be released.
  -  Added `IncompleteBlockStatesException` class.  [[#272], [#285]]
  -  Added `completeStates` option to `BlockChain<T>.GetStates()` method.
     [[#272], [#285]]
+ -  Added `BlockChain<T>.MakeTransaction(PrivateKey, IEnumerable<T>,
+    IImmutableSet<Address>, DateTimeOffset?)` method.  [[#294]]
 
 ### Behavioral changes
 
@@ -65,6 +69,7 @@ To be released.
 [#281]: https://github.com/planetarium/libplanet/pull/281
 [#285]: https://github.com/planetarium/libplanet/pull/285
 [#287]: https://github.com/planetarium/libplanet/pull/287
+[#294]: https://github.com/planetarium/libplanet/pull/294
 
 
 Version 0.3.0
diff --git a/Libplanet.Tests/Blockchain/BlockChainTest.cs b/Libplanet.Tests/Blockchain/BlockChainTest.cs
index 7a103f82297..b9eebc911a7 100644
--- a/Libplanet.Tests/Blockchain/BlockChainTest.cs
+++ b/Libplanet.Tests/Blockchain/BlockChainTest.cs
@@ -488,7 +488,7 @@ public void ForkTxNonce()
                 _fx.MakeTransaction(actions, privateKey: privateKey),
             };
 
-            Assert.Equal(0, _blockChain.GetNonce(address));
+            Assert.Equal(0, _blockChain.GetNextTxNonce(address));
 
             Block<DumbAction> b1 = TestUtils.MineNext(
                 genesis,
@@ -497,7 +497,7 @@ public void ForkTxNonce()
                 _blockChain.Policy.GetNextBlockDifficulty(_blockChain));
             _blockChain.Append(b1);
 
-            Assert.Equal(1, _blockChain.GetNonce(address));
+            Assert.Equal(1, _blockChain.GetNextTxNonce(address));
 
             Transaction<DumbAction>[] txsB =
             {
@@ -513,10 +513,10 @@ public void ForkTxNonce()
                 _blockChain.Policy.GetNextBlockDifficulty(_blockChain));
             _blockChain.Append(b2);
 
-            Assert.Equal(2, _blockChain.GetNonce(address));
+            Assert.Equal(2, _blockChain.GetNextTxNonce(address));
 
             BlockChain<DumbAction> forked = _blockChain.Fork(b1.Hash);
-            Assert.Equal(1, forked.GetNonce(address));
+            Assert.Equal(1, forked.GetNextTxNonce(address));
         }
 
         [Fact]
@@ -863,18 +863,18 @@ public void EvaluateActions()
         }
 
         [Fact]
-        public void GetNonce()
+        public void GetNextTxNonce()
         {
             var privateKey = new PrivateKey();
             Address address = privateKey.PublicKey.ToAddress();
             var actions = new[] { new DumbAction(_fx.Address1, "foo") };
 
-            Assert.Equal(0, _blockChain.GetNonce(address));
+            Assert.Equal(0, _blockChain.GetNextTxNonce(address));
 
             Block<DumbAction> genesis = TestUtils.MineGenesis<DumbAction>();
             _blockChain.Append(genesis);
 
-            Assert.Equal(0, _blockChain.GetNonce(address));
+            Assert.Equal(0, _blockChain.GetNextTxNonce(address));
 
             Transaction<DumbAction>[] txsA =
             {
@@ -888,7 +888,7 @@ public void GetNonce()
                 _blockChain.Policy.GetNextBlockDifficulty(_blockChain));
             _blockChain.Append(b1);
 
-            Assert.Equal(1, _blockChain.GetNonce(address));
+            Assert.Equal(1, _blockChain.GetNextTxNonce(address));
 
             Transaction<DumbAction>[] txsB =
             {
@@ -898,7 +898,7 @@ public void GetNonce()
 
             _blockChain.StageTransactions(txsB.ToHashSet());
 
-            Assert.Equal(3, _blockChain.GetNonce(address));
+            Assert.Equal(3, _blockChain.GetNextTxNonce(address));
 
             Transaction<DumbAction>[] txsC =
             {
@@ -907,7 +907,62 @@ public void GetNonce()
             };
             _blockChain.StageTransactions(txsC.ToHashSet());
 
-            Assert.Equal(4, _blockChain.GetNonce(address));
+            Assert.Equal(4, _blockChain.GetNextTxNonce(address));
+        }
+
+        [Fact]
+        public void ValidateNonce()
+        {
+            var privateKey = new PrivateKey();
+            var actions = new[] { new DumbAction() };
+
+            Block<DumbAction> genesis = TestUtils.MineGenesis<DumbAction>();
+            _blockChain.Append(genesis);
+
+            Transaction<DumbAction>[] txsA =
+            {
+                _fx.MakeTransaction(actions, privateKey: privateKey, nonce: 1),
+                _fx.MakeTransaction(actions, privateKey: privateKey, nonce: 0),
+            };
+            Block<DumbAction> b1 = TestUtils.MineNext(genesis, txsA);
+            _blockChain.ValidateNonce(b1);
+
+            Transaction<DumbAction>[] txsB =
+            {
+                _fx.MakeTransaction(actions, privateKey: privateKey, nonce: 1),
+            };
+            Block<DumbAction> b2 = TestUtils.MineNext(genesis, txsB);
+            Assert.Throws<InvalidTxNonceException>(() =>
+                _blockChain.ValidateNonce(b2));
+        }
+
+        [Fact]
+        public void MakeTransaction()
+        {
+            var privateKey = new PrivateKey();
+            Address address = privateKey.PublicKey.ToAddress();
+            var actions = new[] { new DumbAction(address, "foo") };
+
+            _blockChain.MakeTransaction(privateKey, actions);
+            _blockChain.MakeTransaction(privateKey, actions);
+
+            List<Transaction<DumbAction>> txs = _blockChain.Store
+                .IterateStagedTransactionIds()
+                .Select(_blockChain.Store.GetTransaction<DumbAction>)
+                .OrderBy(tx => tx.Nonce)
+                .ToList();
+
+            Assert.Equal(2, txs.Count());
+
+            var transaction = txs[0];
+            Assert.Equal(0, transaction.Nonce);
+            Assert.Equal(address, transaction.Signer);
+            Assert.Equal(actions, transaction.Actions);
+
+            transaction = txs[1];
+            Assert.Equal(1, transaction.Nonce);
+            Assert.Equal(address, transaction.Signer);
+            Assert.Equal(actions, transaction.Actions);
         }
 
         /// <summary>
diff --git a/Libplanet/Blockchain/BlockChain.cs b/Libplanet/Blockchain/BlockChain.cs
index a974b4dae6b..2032b2dfb0b 100644
--- a/Libplanet/Blockchain/BlockChain.cs
+++ b/Libplanet/Blockchain/BlockChain.cs
@@ -9,6 +9,7 @@
 using Libplanet.Action;
 using Libplanet.Blockchain.Policies;
 using Libplanet.Blocks;
+using Libplanet.Crypto;
 using Libplanet.Store;
 using Libplanet.Tx;
 
@@ -19,6 +20,7 @@ public class BlockChain<T> : IReadOnlyList<Block<T>>
         where T : IAction, new()
     {
         private readonly ReaderWriterLockSlim _rwlock;
+        private readonly object _txLock;
 
         public BlockChain(IBlockPolicy<T> policy, IStore store)
             : this(policy, store, Guid.NewGuid())
@@ -35,6 +37,7 @@ public BlockChain(IBlockPolicy<T> policy, IStore store, Guid id)
 
             _rwlock = new ReaderWriterLockSlim(
                 LockRecursionPolicy.SupportsRecursion);
+            _txLock = new object();
         }
 
         ~BlockChain()
@@ -291,7 +294,7 @@ public AddressStateMap GetStates(
         /// the <see cref="Policy"/>.</exception>
         /// <exception cref="InvalidTxNonceException">Thrown when the
         /// <see cref="Transaction{T}.Nonce"/> is different from
-        /// <see cref="BlockChain{T}.GetNonce"/> result of the
+        /// <see cref="GetNextTxNonce"/> result of the
         /// <see cref="Transaction{T}.Signer"/>.</exception>
         public void Append(Block<T> block) =>
             Append(block, DateTimeOffset.UtcNow);
@@ -312,7 +315,7 @@ public void Append(Block<T> block) =>
         /// the <see cref="Policy"/>.</exception>
         /// <exception cref="InvalidTxNonceException">Thrown when the
         /// <see cref="Transaction{T}.Nonce"/> is different from
-        /// <see cref="BlockChain{T}.GetNonce"/> result of the
+        /// <see cref="GetNextTxNonce"/> result of the
         /// <see cref="Transaction{T}.Signer"/>.</exception>
         public void Append(Block<T> block, DateTimeOffset currentTime) =>
             Append(block, currentTime, render: true);
@@ -348,7 +351,14 @@ public void UnstageTransactions(ISet<Transaction<T>> transactions)
                 transactions.Select(tx => tx.Id).ToImmutableHashSet());
         }
 
-        public long GetNonce(Address address)
+        /// <summary>
+        /// Gets next <see cref="Transaction{T}.Nonce"/> of the address.
+        /// </summary>
+        /// <param name="address">The <see cref="Address"/> from which to obtain the
+        /// <see cref="Transaction{T}.Nonce"/> value.</param>
+        /// <returns>The next <see cref="Transaction{T}.Nonce"/> value of the
+        /// <paramref name="address"/>.</returns>
+        public long GetNextTxNonce(Address address)
         {
             long nonce = Store.GetTxNonce(Id.ToString(), address);
 
@@ -380,11 +390,9 @@ DateTimeOffset currentTime
                 @namespace,
                 index - 1
             );
-            List<Transaction<T>> transactions = Store
+            IEnumerable<Transaction<T>> transactions = Store
                 .IterateStagedTransactionIds()
-                .Select(Store.GetTransaction<T>)
-                .OrderBy(tx => tx.Nonce)
-                .ToList();
+                .Select(Store.GetTransaction<T>);
 
             Block<T> block = Block<T>.Mine(
                 index: index,
@@ -402,6 +410,41 @@ DateTimeOffset currentTime
         public Block<T> MineBlock(Address miner) =>
             MineBlock(miner, DateTimeOffset.UtcNow);
 
+        /// <summary>
+        /// Creates a new <see cref="Transaction{T}"/> and stage the transaction.
+        /// </summary>
+        /// <param name="privateKey">A <see cref="PrivateKey"/> of the account who creates and
+        /// signs a new transaction.</param>
+        /// <param name="actions">A list of <see cref="IAction"/>s to include to a new transaction.
+        /// </param>
+        /// <param name="updatedAddresses"><see cref="Address"/>es whose states affected by
+        /// <paramref name="actions"/>.</param>
+        /// <param name="timestamp">The time this <see cref="Transaction{T}"/> is created and
+        /// signed.</param>
+        /// <returns>A created new <see cref="Transaction{T}"/> signed by the given
+        /// <paramref name="privateKey"/>.</returns>
+        /// <seealso cref="Transaction{T}.Create" />
+        public Transaction<T> MakeTransaction(
+            PrivateKey privateKey,
+            IEnumerable<T> actions,
+            IImmutableSet<Address> updatedAddresses = null,
+            DateTimeOffset? timestamp = null)
+        {
+            timestamp = timestamp ?? DateTimeOffset.UtcNow;
+            lock (_txLock)
+            {
+                Transaction<T> tx = Transaction<T>.Create(
+                    GetNextTxNonce(privateKey.PublicKey.ToAddress()),
+                    privateKey,
+                    actions,
+                    updatedAddresses,
+                    timestamp);
+                StageTransactions(new HashSet<Transaction<T>> { tx });
+
+                return tx;
+            }
+        }
+
         internal void Append(
             Block<T> block,
             DateTimeOffset currentTime,
diff --git a/Libplanet/Blockchain/MineBlockEventArgs.cs b/Libplanet/Blockchain/MineBlockEventArgs.cs
new file mode 100644
index 00000000000..22ba82d9c98
--- /dev/null
+++ b/Libplanet/Blockchain/MineBlockEventArgs.cs
@@ -0,0 +1,16 @@
+using Libplanet.Action;
+using Libplanet.Blocks;
+
+namespace Libplanet.Blockchain
+{
+    public class MineBlockEventArgs<T>
+        where T : IAction, new()
+    {
+        public MineBlockEventArgs(Block<T> block)
+        {
+            Block = block;
+        }
+
+        public Block<T> Block { get; }
+    }
+}
diff --git a/Libplanet/Blocks/Block.cs b/Libplanet/Blocks/Block.cs
index 361cb9fb4dc..99f36a41544 100644
--- a/Libplanet/Blocks/Block.cs
+++ b/Libplanet/Blocks/Block.cs
@@ -38,7 +38,10 @@ public Block(
             Miner = miner;
             PreviousHash = previousHash;
             Timestamp = timestamp;
-            Transactions = transactions;
+
+            // FIXME: We need to fix this to solve
+            // https://github.com/planetarium/libplanet/issues/244.
+            Transactions = transactions.OrderBy(tx => tx.Nonce).ToList();
             Hash = Hashcash.Hash(ToBencodex(false, false));
         }
 
diff --git a/Libplanet/Tx/InvalidTxNonceException.cs b/Libplanet/Tx/InvalidTxNonceException.cs
index ecd4e563083..cedc2326934 100644
--- a/Libplanet/Tx/InvalidTxNonceException.cs
+++ b/Libplanet/Tx/InvalidTxNonceException.cs
@@ -6,7 +6,7 @@ namespace Libplanet.Tx
 {
     /// <summary>
     /// The exception that is thrown when the <see cref="Transaction{T}.Nonce"/>
-    /// is different from <see cref="BlockChain{T}.GetNonce"/> result of
+    /// is different from <see cref="BlockChain{T}.GetNextTxNonce"/> result of
     /// the <see cref="Transaction{T}.Signer"/>.
     /// </summary>
     [Serializable]
@@ -19,7 +19,7 @@ public sealed class InvalidTxNonceException : InvalidTxException
         /// <param name="txid">The invalid <see cref="Transaction{T}"/>'s
         /// <see cref="Transaction{T}.Id"/>.  It is automatically included to
         /// the <see cref="Exception.Message"/> string.</param>
-        /// <param name="expectedNonce"><see cref="BlockChain{T}.GetNonce"/>
+        /// <param name="expectedNonce"><see cref="BlockChain{T}.GetNextTxNonce"/>
         /// result of the <see cref="Transaction{T}.Signer"/>.</param>
         /// <param name="improperNonce">The actual
         /// <see cref="Transaction{T}.Nonce"/>.</param>
@@ -44,7 +44,7 @@ public InvalidTxNonceException(
         }
 
         /// <summary>
-        /// <see cref="BlockChain{T}.GetNonce"/> result of the
+        /// <see cref="BlockChain{T}.GetNextTxNonce"/> result of the
         /// <see cref="Transaction{T}.Signer"/>.
         /// </summary>
         public long ExpectedNonce { get; }