diff --git a/YamlDotNet.Test/Serialization/SerializationTests.cs b/YamlDotNet.Test/Serialization/SerializationTests.cs
index 0d619904a..d30c5968e 100644
--- a/YamlDotNet.Test/Serialization/SerializationTests.cs
+++ b/YamlDotNet.Test/Serialization/SerializationTests.cs
@@ -164,6 +164,36 @@ public void DeserializeScalarLongBase60Number()
             result.Should().Be(77744246530L);
         }
 
+        [Theory]
+        [InlineData("0o0", 0)]
+        [InlineData("0x8000", 32768)]
+        [InlineData("0xFFFFFFFFFFFFFFFF", 18_446_744_073_709_551_615)]
+        public void DeserializeScalarBase16FromUnknown(string yaml, ulong value)
+        {
+            IDeserializer deserializer = new DeserializerBuilder()
+                .WithAttemptingUnquotedStringTypeDeserialization()
+                .Build();
+
+            var result = deserializer.Deserialize<object>(new StringReader(yaml));
+
+            result.Should().Be(value);
+        }
+
+        [Theory]
+        [InlineData("0o0", 0)]
+        [InlineData("0o100000", 32768)]
+        [InlineData("0o1777777777777777777777", 18_446_744_073_709_551_615)]
+        public void DeserializeScalarBase8FromUnknown(string yaml, ulong value)
+        {
+            IDeserializer deserializer = new DeserializerBuilder()
+                .WithAttemptingUnquotedStringTypeDeserialization()
+                .Build();
+
+            var result = deserializer.Deserialize<object>(new StringReader(yaml));
+
+            result.Should().Be(value);
+        }
+
         [Theory]
         [InlineData(EnumExample.One)]
         [InlineData(EnumExample.One | EnumExample.Two)]
diff --git a/YamlDotNet/Serialization/NodeDeserializers/ScalarNodeDeserializer.cs b/YamlDotNet/Serialization/NodeDeserializers/ScalarNodeDeserializer.cs
index 175376ee0..47a2d2f5a 100644
--- a/YamlDotNet/Serialization/NodeDeserializers/ScalarNodeDeserializer.cs
+++ b/YamlDotNet/Serialization/NodeDeserializers/ScalarNodeDeserializer.cs
@@ -355,24 +355,16 @@ private static object CastInteger(ulong number, TypeCode typeCode)
                 default:
                     if (Regex.IsMatch(v, "0x[0-9a-fA-F]+")) //base16 number
                     {
-                        if (TryAndSwallow(() => Convert.ToByte(v, 16), out result)) { }
-                        else if (TryAndSwallow(() => Convert.ToInt16(v, 16), out result)) { }
-                        else if (TryAndSwallow(() => Convert.ToInt32(v, 16), out result)) { }
-                        else if (TryAndSwallow(() => Convert.ToInt64(v, 16), out result)) { }
-                        else if (TryAndSwallow(() => Convert.ToUInt64(v, 16), out result)) { }
+                        if (TryAndSwallow(() => Convert.ToUInt64(v, 16), out result)) { }
                         else
                         {
                             //we couldn't parse it, default to a string. It's probably to big.
                             result = v;
                         }
                     }
-                    else if (Regex.IsMatch(v, "0o[0-9a-fA-F]+")) //base8 number
+                    else if (Regex.IsMatch(v, "0o[0-7]+")) //base8 number
                     {
-                        if (TryAndSwallow(() => Convert.ToByte(v, 8), out result)) { }
-                        else if (TryAndSwallow(() => Convert.ToInt16(v, 8), out result)) { }
-                        else if (TryAndSwallow(() => Convert.ToInt32(v, 8), out result)) { }
-                        else if (TryAndSwallow(() => Convert.ToInt64(v, 8), out result)) { }
-                        else if (TryAndSwallow(() => Convert.ToUInt64(v, 8), out result)) { }
+                        if (TryAndSwallow(() => Convert.ToUInt64(v.Substring(2), 8), out result)) { }
                         else
                         {
                             //we couldn't parse it, default to a string. It's probably to big.