diff --git a/test/state/errors.hpp b/test/state/errors.hpp
index 8c4afd64c2..5c71081019 100644
--- a/test/state/errors.hpp
+++ b/test/state/errors.hpp
@@ -32,6 +32,7 @@ enum ErrorCode : int  // NOLINT(*-use-enum-class)
     EMPTY_AUTHORIZATION_LIST,
     MAX_GAS_LIMIT_EXCEEDED,
     INVALID_CHAIN_ID,
+    INVALID_ENCODING,
     UNKNOWN_ERROR,
 
     // Block-level validation.
@@ -103,6 +104,8 @@ inline const std::error_category& evmone_category() noexcept
                 return "max gas limit exceeded";
             case INVALID_CHAIN_ID:
                 return "invalid transaction chain id";
+            case INVALID_ENCODING:
+                return "invalid transaction encoding";
             case UNKNOWN_ERROR:
                 return "Unknown error";
             case INCORRECT_BLOCK_FORMAT:
diff --git a/test/statetest/statetest_runner.cpp b/test/statetest/statetest_runner.cpp
index 6c607c19f1..cb6765461e 100644
--- a/test/statetest/statetest_runner.cpp
+++ b/test/statetest/statetest_runner.cpp
@@ -24,12 +24,24 @@ void run_state_test(const StateTransitionTest& test, evmc::VM& vm, bool trace_su
             //     continue;
 
             const auto& expected = cases[case_index];
-            const auto tx = test.multi_tx.get(expected.indexes);
             auto state = test.pre_state;
             const auto blob_params = get_blob_params(rev, test.blob_schedule);
 
-            const auto res = transition(state, block, test.block_hashes, tx, rev, vm,
-                block.gas_limit, static_cast<int64_t>(state::max_blob_gas_per_block(blob_params)));
+            // Decode transaction from txbytes if available.
+            const auto template_tx = test.multi_tx.get(expected.indexes);
+            auto tx = std::optional{template_tx};
+            if (expected.txbytes.has_value())
+            {
+                tx = state::decode_transaction(*expected.txbytes);
+                if (tx.has_value())
+                    tx->sender = template_tx.sender;  // No recovery yet, take sender from JSON.
+            }
+
+            const auto res =
+                tx.has_value() ?
+                    transition(state, block, test.block_hashes, *tx, rev, vm, block.gas_limit,
+                        static_cast<int64_t>(state::max_blob_gas_per_block(blob_params))) :
+                    make_error_code(state::INVALID_ENCODING);
 
             if (holds_alternative<state::TransactionReceipt>(res))
             {
diff --git a/test/utils/statetest.hpp b/test/utils/statetest.hpp
index ea42821c7a..55c096832d 100644
--- a/test/utils/statetest.hpp
+++ b/test/utils/statetest.hpp
@@ -51,6 +51,9 @@ struct StateTransitionTest
             hash256 state_hash;
             hash256 logs_hash = EmptyListHash;
             bool exception = false;
+
+            /// The full encoded transaction for this case. Not always available.
+            std::optional<bytes> txbytes;
         };
 
         evmc_revision rev;
diff --git a/test/utils/statetest_loader.cpp b/test/utils/statetest_loader.cpp
index 9b0a74879b..c17f1bf15f 100644
--- a/test/utils/statetest_loader.cpp
+++ b/test/utils/statetest_loader.cpp
@@ -494,6 +494,9 @@ static void from_json(const json::json& j, StateTransitionTest::Case::Expectatio
     o.state_hash = from_json<hash256>(j.at("hash"));
     o.logs_hash = from_json<hash256>(j.at("logs"));
     o.exception = j.contains("expectException");
+    // Not load_if_exists(): it maps an absent key to bytes{}, which engages the optional.
+    if (const auto it = j.find("txbytes"); it != j.end())
+        o.txbytes = from_json<bytes>(*it);
 }
 
 static void from_json(const json::json& j_t, StateTransitionTest& o)