diff --git a/tests/core/pyspec/eth2spec/test/bellatrix/sanity/test_blocks.py b/tests/core/pyspec/eth2spec/test/bellatrix/sanity/test_blocks.py
index 75dfa0c9cf..6ac76ca596 100644
--- a/tests/core/pyspec/eth2spec/test/bellatrix/sanity/test_blocks.py
+++ b/tests/core/pyspec/eth2spec/test/bellatrix/sanity/test_blocks.py
@@ -33,7 +33,7 @@ def test_empty_block_transition_no_tx(spec, state):
 
 @with_bellatrix_and_later
 @spec_state_test
-def test_empty_block_transition_randomized_payload(spec, state):
+def test_block_transition_randomized_payload(spec, state):
     yield 'pre', state
 
     block = build_empty_block_for_next_slot(spec, state)
diff --git a/tests/core/pyspec/eth2spec/test/deneb/sanity/test_blocks.py b/tests/core/pyspec/eth2spec/test/deneb/sanity/test_blocks.py
index eecd7ad469..5c9cd6e2ca 100644
--- a/tests/core/pyspec/eth2spec/test/deneb/sanity/test_blocks.py
+++ b/tests/core/pyspec/eth2spec/test/deneb/sanity/test_blocks.py
@@ -1,3 +1,5 @@
+import random
+
 from eth2spec.test.helpers.state import (
     state_transition_and_sign_block,
     next_epoch_via_block,
@@ -15,6 +17,7 @@
 )
 from eth2spec.test.helpers.execution_payload import (
     compute_el_block_hash,
+    get_random_tx,
 )
 from eth2spec.test.helpers.attestations import (
     get_valid_attestation,
@@ -24,7 +27,8 @@
 )
 
 
-def run_block_with_blobs(spec, state, blob_count, data_gas_used=1, excess_data_gas=1, valid=True, tx_count=1):
+def run_block_with_blobs(spec, state, blob_count, tx_count=1, data_gas_used=1, excess_data_gas=1,
+                         non_blob_tx_count=0, rng=random.Random(7777), valid=True):
     yield 'pre', state
 
     block = build_empty_block_for_next_slot(spec, state)
@@ -35,6 +39,9 @@ def run_block_with_blobs(spec, state, blob_count, data_gas_used=1, excess_data_g
         txs.append(opaque_tx)
         blob_kzg_commitments += commits
 
+    for _ in range(non_blob_tx_count):
+        txs.append(get_random_tx(rng=rng))
+
     block.body.blob_kzg_commitments = blob_kzg_commitments
     block.body.execution_payload.transactions = txs
     block.body.execution_payload.data_gas_used = data_gas_used
@@ -98,6 +105,12 @@ def test_invalid_exceed_max_blobs_per_block(spec, state):
     yield from run_block_with_blobs(spec, state, blob_count=spec.MAX_BLOBS_PER_BLOCK + 1, valid=False)
 
 
+@with_deneb_and_later
+@spec_state_test
+def test_mix_blob_tx_and_non_blob_tx(spec, state):
+    yield from run_block_with_blobs(spec, state, blob_count=1, tx_count=1, non_blob_tx_count=1)
+
+
 @with_phases([DENEB])
 @spec_configured_state_test({
     'DENEB_FORK_EPOCH': 2,
diff --git a/tests/core/pyspec/eth2spec/test/helpers/execution_payload.py b/tests/core/pyspec/eth2spec/test/helpers/execution_payload.py
index 2f9c0e0a46..00f7a4bb7b 100644
--- a/tests/core/pyspec/eth2spec/test/helpers/execution_payload.py
+++ b/tests/core/pyspec/eth2spec/test/helpers/execution_payload.py
@@ -259,7 +259,7 @@ def build_randomized_execution_payload(spec, state, rng):
 
     num_transactions = rng.randint(0, 100)
     execution_payload.transactions = [
-        spec.Transaction(get_random_bytes_list(rng, rng.randint(0, 1000)))
+        get_random_tx(rng)
         for _ in range(num_transactions)
     ]
 
@@ -290,3 +290,7 @@ def build_state_with_execution_payload_header(spec, state, execution_payload_hea
     pre_state.latest_execution_payload_header = execution_payload_header
 
     return pre_state
+
+
+def get_random_tx(rng):
+    return get_random_bytes_list(rng, rng.randint(0, 1000))
diff --git a/tests/core/pyspec/eth2spec/test/utils/randomized_block_tests.py b/tests/core/pyspec/eth2spec/test/utils/randomized_block_tests.py
index c164515103..3255de87a6 100644
--- a/tests/core/pyspec/eth2spec/test/utils/randomized_block_tests.py
+++ b/tests/core/pyspec/eth2spec/test/utils/randomized_block_tests.py
@@ -9,6 +9,7 @@
 
 from eth2spec.test.helpers.execution_payload import (
     compute_el_block_hash,
+    build_randomized_execution_payload,
 )
 from eth2spec.test.helpers.multi_operations import (
     build_random_block_from_state_for_next_slot,
@@ -216,14 +217,17 @@ def random_block_altair_with_cycling_sync_committee_participation(spec,
     return block
 
 
-def random_block_bellatrix(spec, state, signed_blocks, scenario_state):
+def random_block_bellatrix(spec, state, signed_blocks, scenario_state, rng=Random(3456)):
     block = random_block_altair_with_cycling_sync_committee_participation(spec, state, signed_blocks, scenario_state)
-    # TODO: return randomized execution payload
+    # build execution_payload at the next slot
+    state = state.copy()
+    next_slot(spec, state)
+    block.body.execution_payload = build_randomized_execution_payload(spec, state, rng=rng)
     return block
 
 
 def random_block_capella(spec, state, signed_blocks, scenario_state, rng=Random(3456)):
-    block = random_block_bellatrix(spec, state, signed_blocks, scenario_state)
+    block = random_block_bellatrix(spec, state, signed_blocks, scenario_state, rng=rng)
     block.body.bls_to_execution_changes = get_random_bls_to_execution_changes(
         spec,
         state,
@@ -233,10 +237,11 @@ def random_block_capella(spec, state, signed_blocks, scenario_state, rng=Random(
 
 
 def random_block_deneb(spec, state, signed_blocks, scenario_state, rng=Random(3456)):
-    block = random_block_capella(spec, state, signed_blocks, scenario_state)
+    block = random_block_capella(spec, state, signed_blocks, scenario_state, rng=rng)
     # TODO: more commitments. blob_kzg_commitments: List[KZGCommitment, MAX_BLOBS_PER_BLOCK]
-    opaque_tx, _, blob_kzg_commitments, _ = get_sample_opaque_tx(spec, blob_count=1)
-    block.body.execution_payload.transactions = [opaque_tx]
+    opaque_tx, _, blob_kzg_commitments, _ = get_sample_opaque_tx(
+        spec, blob_count=rng.randint(0, spec.MAX_BLOBS_PER_BLOCK), rng=rng)
+    block.body.execution_payload.transactions.append(opaque_tx)
     block.body.execution_payload.block_hash = compute_el_block_hash(spec, block.body.execution_payload)
     block.body.blob_kzg_commitments = blob_kzg_commitments