diff --git a/circle.yml b/circle.yml
index e4312be3ab..5ed32911fb 100644
--- a/circle.yml
+++ b/circle.yml
@@ -19,7 +19,7 @@ commands:
     steps:
       - restore_cache:
           name: "Restore Silkworm cache"
-          key: &silkworm-cache-key silkworm-20210413
+          key: &silkworm-cache-key silkworm-eip-3198-20210529
       - run:
           name: "Check Silkworm cache"
           command: |
@@ -38,8 +38,8 @@ commands:
           working_directory: ~/silkworm/src
           command: |
             [ "$SILKWORM_BUILD" = true ] || exit 0
-            git clone --no-checkout --single-branch https://github.com/torquem-ch/silkworm.git .
-            git checkout 3388d3ef7ba37ca440707a96a7d2886989073a59
+            git clone --no-checkout --single-branch https://github.com/torquem-ch/silkworm.git . --branch eip-3198
+            git checkout 07a4b7ab2849dc759249b204a455e309ab096412
             git submodule update --init --recursive --depth=1 --progress
       - run:
           name: "Configure Silkworm"
diff --git a/evmc b/evmc
index 53f1fea70f..17fd712701 160000
--- a/evmc
+++ b/evmc
@@ -1 +1 @@
-Subproject commit 53f1fea70ff9e04887b11e34cdf7baab0d4be46c
+Subproject commit 17fd712701502ffe0588df34f006a7ef3d2f954e
diff --git a/lib/evmone/baseline.cpp b/lib/evmone/baseline.cpp
index e9b5f5dcc1..5bce7a8b89 100644
--- a/lib/evmone/baseline.cpp
+++ b/lib/evmone/baseline.cpp
@@ -345,6 +345,9 @@ evmc_result execute(const VM& vm, ExecutionState& state, const CodeAnalysis& ana
         case OP_SELFBALANCE:
             selfbalance(state);
             break;
+        case OP_BASEFEE:
+            basefee(state);
+            break;
 
         case OP_POP:
             pop(state.stack);
diff --git a/lib/evmone/instruction_traits.hpp b/lib/evmone/instruction_traits.hpp
index f2b094c36a..53044c7025 100644
--- a/lib/evmone/instruction_traits.hpp
+++ b/lib/evmone/instruction_traits.hpp
@@ -94,6 +94,7 @@ constexpr inline std::array<Traits, 256> traits = []() noexcept {
     table[OP_GASLIMIT] = {"GASLIMIT", 0, 1};
     table[OP_CHAINID] = {"CHAINID", 0, 1};
     table[OP_SELFBALANCE] = {"SELFBALANCE", 0, 1};
+    table[OP_BASEFEE] = {"BASEFEE", 0, 1};
 
     table[OP_POP] = {"POP", 1, -1};
     table[OP_MLOAD] = {"MLOAD", 1, 0};
@@ -365,6 +366,7 @@ constexpr inline std::array<int16_t, 256> gas_costs<EVMC_BERLIN> = []() noexcept
 template <>
 constexpr inline std::array<int16_t, 256> gas_costs<EVMC_LONDON> = []() noexcept {
     auto table = gas_costs<EVMC_BERLIN>;
+    table[OP_BASEFEE] = 2;
     return table;
 }();
 
diff --git a/lib/evmone/instructions.cpp b/lib/evmone/instructions.cpp
index f44539614a..302f7d5bb9 100644
--- a/lib/evmone/instructions.cpp
+++ b/lib/evmone/instructions.cpp
@@ -253,6 +253,7 @@ constexpr std::array<instruction_exec_fn, 256> instruction_implementations = [](
     table[OP_GASLIMIT] = op<gaslimit>;
     table[OP_CHAINID] = op<chainid>;
     table[OP_SELFBALANCE] = op<selfbalance>;
+    table[OP_BASEFEE] = op<basefee>;
 
     table[OP_POP] = op<pop>;
     table[OP_MLOAD] = op<mload>;
diff --git a/lib/evmone/instructions.hpp b/lib/evmone/instructions.hpp
index 3003de1bec..10fb59cb76 100644
--- a/lib/evmone/instructions.hpp
+++ b/lib/evmone/instructions.hpp
@@ -403,6 +403,11 @@ inline void gasprice(ExecutionState& state) noexcept
     state.stack.push(intx::be::load<uint256>(state.host.get_tx_context().tx_gas_price));
 }
 
+inline void basefee(ExecutionState& state) noexcept
+{
+    state.stack.push(intx::be::load<uint256>(state.host.get_tx_context().block_base_fee));
+}
+
 inline evmc_status_code extcodesize(ExecutionState& state) noexcept
 {
     auto& x = state.stack.top();
diff --git a/test/unittests/CMakeLists.txt b/test/unittests/CMakeLists.txt
index 54940c2b56..a7e60aa506 100644
--- a/test/unittests/CMakeLists.txt
+++ b/test/unittests/CMakeLists.txt
@@ -14,6 +14,7 @@ add_executable(evmone-unittests
     evm_test.cpp
     evm_calls_test.cpp
     evm_eip2929_test.cpp
+    evm_eip3198_basefee_test.cpp
     evm_state_test.cpp
     evm_other_test.cpp
     evmone_test.cpp
diff --git a/test/unittests/evm_eip3198_basefee_test.cpp b/test/unittests/evm_eip3198_basefee_test.cpp
new file mode 100644
index 0000000000..74607b489c
--- /dev/null
+++ b/test/unittests/evm_eip3198_basefee_test.cpp
@@ -0,0 +1,34 @@
+// evmone: Fast Ethereum Virtual Machine implementation
+// Copyright 2021 The evmone Authors.
+// SPDX-License-Identifier: Apache-2.0
+
+/// This file contains EVM unit tests for EIP-3198 "BASEFEE opcode"
+/// https://eips.ethereum.org/EIPS/eip-3198
+
+#include "evm_fixture.hpp"
+
+using namespace evmc::literals;
+using evmone::test::evm;
+
+TEST_P(evm, basefee_pre_london)
+{
+    rev = EVMC_BERLIN;
+    const auto code = bytecode{OP_BASEFEE};
+
+    execute(code);
+    EXPECT_STATUS(EVMC_UNDEFINED_INSTRUCTION);
+}
+
+TEST_P(evm, basefee_nominal_case)
+{
+    // https://eips.ethereum.org/EIPS/eip-3198#nominal-case
+    rev = EVMC_LONDON;
+    host.tx_context.block_base_fee = evmc::bytes32{7};
+
+    execute(bytecode{} + OP_BASEFEE + OP_STOP);
+    EXPECT_GAS_USED(EVMC_SUCCESS, 2);
+
+    execute(bytecode{} + OP_BASEFEE + ret_top());
+    EXPECT_GAS_USED(EVMC_SUCCESS, 17);
+    EXPECT_OUTPUT_INT(7);
+}