diff --git a/beacon_chain/spec/state_transition_block.nim b/beacon_chain/spec/state_transition_block.nim
index b2b15b84f..9e144a93e 100644
--- a/beacon_chain/spec/state_transition_block.nim
+++ b/beacon_chain/spec/state_transition_block.nim
@@ -140,37 +140,41 @@ func is_slashable_validator(validator: Validator, epoch: Epoch): bool =
     (epoch < validator.withdrawable_epoch)
 
 # https://github.com/ethereum/eth2.0-specs/blob/v0.8.3/specs/core/0_beacon-chain.md#proposer-slashings
-proc process_proposer_slashing(
+proc process_proposer_slashing*(
     state: var BeaconState, proposer_slashing: ProposerSlashing,
     flags: UpdateFlags, stateCache: var StateCache): bool =
+  if proposer_slashing.proposer_index.int >= state.validators.len:
+    notice "Proposer slashing: invalid proposer index"
+    return false
+
   let proposer = state.validators[proposer_slashing.proposer_index.int]
 
   # Verify that the epoch is the same
   if not (compute_epoch_of_slot(proposer_slashing.header_1.slot) ==
       compute_epoch_of_slot(proposer_slashing.header_2.slot)):
-    notice "PropSlash: epoch mismatch"
+    notice "Proposer slashing: epoch mismatch"
     return false
 
   # But the headers are different
   if not (proposer_slashing.header_1 != proposer_slashing.header_2):
-    notice "PropSlash: headers not different"
+    notice "Proposer slashing: headers not different"
     return false
 
   # Check proposer is slashable
   if not is_slashable_validator(proposer, get_current_epoch(state)):
-    notice "PropSlash: slashed proposer"
+    notice "Proposer slashing: slashed proposer"
     return false
 
   # Signatures are valid
   if skipValidation notin flags:
-    for i, header in @[proposer_slashing.header_1, proposer_slashing.header_2]:
+    for i, header in [proposer_slashing.header_1, proposer_slashing.header_2]:
       if not bls_verify(
           proposer.pubkey,
           signing_root(header).data,
           header.signature,
           get_domain(
             state, DOMAIN_BEACON_PROPOSER, compute_epoch_of_slot(header.slot))):
-        notice "PropSlash: invalid signature",
+        notice "Proposer slashing: invalid signature",
           signature_index = i
         return false
 
diff --git a/tests/official/all_fixtures_require_ssz.nim b/tests/official/all_fixtures_require_ssz.nim
index fa6a29a7a..3ff23d060 100644
--- a/tests/official/all_fixtures_require_ssz.nim
+++ b/tests/official/all_fixtures_require_ssz.nim
@@ -14,6 +14,7 @@ import
   ./test_fixture_sanity_blocks,
   ./test_fixture_state_transition_epoch,
   ./test_fixture_operations_attestations,
+  ./test_fixture_operations_attester_slashings,
   ./test_fixture_operations_block_header,
-  ./test_fixture_operations_voluntary_exit,
-  ./test_fixture_operations_attester_slashings
+  ./test_fixture_operations_proposer_slashings,
+  ./test_fixture_operations_voluntary_exit
\ No newline at end of file
diff --git a/tests/official/test_fixture_operations_proposer_slashings.nim b/tests/official/test_fixture_operations_proposer_slashings.nim
new file mode 100644
index 000000000..a77a59007
--- /dev/null
+++ b/tests/official/test_fixture_operations_proposer_slashings.nim
@@ -0,0 +1,76 @@
+# beacon_chain
+# Copyright (c) 2018-Present Status Research & Development GmbH
+# Licensed and distributed under either of
+#   * MIT license (license terms in the root directory or at http://opensource.org/licenses/MIT).
+#   * Apache v2 license (license terms in the root directory or at http://www.apache.org/licenses/LICENSE-2.0).
+# at your option. This file may not be copied, modified, or distributed except according to those terms.
+
+import
+  # Standard library
+  os, unittest, strutils,
+  # Beacon chain internals
+  ../../beacon_chain/spec/[datatypes, state_transition_block, validator],
+  ../../beacon_chain/[ssz, extras],
+  # Test utilities
+  ../testutil,
+  ./fixtures_utils,
+  ../helpers/debug_state
+
+const OpProposerSlashingDir = SszTestsDir/const_preset/"phase0"/"operations"/"proposer_slashing"/"pyspec_tests"
+
+template runTest(identifier: untyped) =
+  # We wrap the tests in a proc to avoid running out of globals
+  # in the future: Nim supports up to 3500 globals
+  # but unittest with the macro/templates put everything as globals
+  # https://github.com/nim-lang/Nim/issues/12084#issue-486866402
+
+  const testDir = OpProposerSlashingDir / astToStr(identifier)
+
+  proc `testImpl_proposer_slashing _ identifier`() =
+
+    var flags: UpdateFlags
+    var prefix: string
+    if not existsFile(testDir/"meta.yaml"):
+      flags.incl skipValidation
+    if existsFile(testDir/"post.ssz"):
+      prefix = "[Valid]   "
+    else:
+      prefix = "[Invalid] "
+
+    test prefix & astToStr(identifier):
+      var stateRef, postRef: ref BeaconState
+      var proposerSlashing: ref ProposerSlashing
+      new proposerSlashing
+      new stateRef
+
+      proposerSlashing[] = parseTest(testDir/"proposer_slashing.ssz", SSZ, ProposerSlashing)
+      stateRef[] = parseTest(testDir/"pre.ssz", SSZ, BeaconState)
+
+      if existsFile(testDir/"post.ssz"):
+        new postRef
+        postRef[] = parseTest(testDir/"post.ssz", SSZ, BeaconState)
+
+      var cache = get_empty_per_epoch_cache()
+
+      if postRef.isNil:
+        let done = process_proposer_slashing(stateRef[], proposerSlashing[], flags, cache)
+        doAssert done == false, "We didn't expect this invalid proposer slashing to be processed."
+      else:
+        let done = process_proposer_slashing(stateRef[], proposerSlashing[], flags, cache)
+        doAssert done, "Valid proposer slashing not processed"
+        check: stateRef.hash_tree_root() == postRef.hash_tree_root()
+        reportDiff(stateRef, postRef)
+
+  `testImpl_proposer_slashing _ identifier`()
+
+suite "Official - Operations - Proposer slashing " & preset():
+  runTest(success)
+  runTest(invalid_sig_1)
+  runTest(invalid_sig_2)
+  runTest(invalid_sig_1_and_2)
+  runTest(invalid_proposer_index)
+  runTest(epochs_are_different)
+  runTest(headers_are_same)
+  runTest(proposer_is_not_activated)
+  runTest(proposer_is_slashed)
+  runTest(proposer_is_withdrawn)