diff --git a/src/ssb.db.c b/src/ssb.db.c
index 0d1de3f9..d48962b2 100644
--- a/src/ssb.db.c
+++ b/src/ssb.db.c
@@ -2918,3 +2918,21 @@ void tf_ssb_db_remove_block(sqlite3* db, const char* id)
 		sqlite3_finalize(statement);
 	}
 }
+
+bool tf_ssb_db_is_blocked(sqlite3* db, const char* id)
+{
+	bool is_blocked = false;
+	sqlite3_stmt* statement = NULL;
+	if (sqlite3_prepare_v2(db, "SELECT 1 FROM blocks WHERE id = ?", -1, &statement, NULL) == SQLITE_OK)
+	{
+		if (sqlite3_bind_text(statement, 1, id, -1, NULL) == SQLITE_OK)
+		{
+			if (sqlite3_step(statement) == SQLITE_ROW)
+			{
+				is_blocked = true;
+			}
+		}
+		sqlite3_finalize(statement);
+	}
+	return is_blocked;
+}
diff --git a/src/ssb.db.h b/src/ssb.db.h
index 5aef1a43..dfde0790 100644
--- a/src/ssb.db.h
+++ b/src/ssb.db.h
@@ -631,4 +631,12 @@ void tf_ssb_db_add_block(sqlite3* db, const char* id);
 */
 void tf_ssb_db_remove_block(sqlite3* db, const char* id);
 
+/**
+** Check if an ID is blocked on this instance.
+** @param db The database.
+** @param id The account, message, or blob ID to check.
+** @return true if the id is blocked.
+*/
+bool tf_ssb_db_is_blocked(sqlite3* db, const char* id);
+
 /** @} */
diff --git a/src/ssb.ebt.c b/src/ssb.ebt.c
index 9c68fc59..d9722f41 100644
--- a/src/ssb.ebt.c
+++ b/src/ssb.ebt.c
@@ -221,6 +221,14 @@ static void _ebt_add_to_clock(ebt_get_clock_t* work, const char* id, int64_t val
 	}
 }
 
+static bool _is_blocked(tf_ssb_t* ssb, const char* id)
+{
+	sqlite3* db = tf_ssb_acquire_db_reader(ssb);
+	bool blocked = tf_ssb_db_is_blocked(db, id);
+	tf_ssb_release_db_reader(ssb, db);
+	return blocked;
+}
+
 static void _tf_ssb_ebt_get_send_clock_work(tf_ssb_connection_t* connection, void* user_data)
 {
 	ebt_get_clock_t* work = user_data;
@@ -239,7 +247,10 @@ static void _tf_ssb_ebt_get_send_clock_work(tf_ssb_connection_t* connection, voi
 		for (int i = 0; visible[i]; i++)
 		{
 			int32_t sequence = 0;
-			tf_ssb_db_get_latest_message_by_author(ssb, visible[i], &sequence, NULL, 0);
+			if (!_is_blocked(ssb, visible[i]))
+			{
+				tf_ssb_db_get_latest_message_by_author(ssb, visible[i], &sequence, NULL, 0);
+			}
 			sequences = tf_resize_vec(sequences, (i + 1) * sizeof(int32_t));
 			sequences[i] = sequence;
 		}
@@ -259,11 +270,14 @@ static void _tf_ssb_ebt_get_send_clock_work(tf_ssb_connection_t* connection, voi
 	char id[k_id_base64_len] = "";
 	if (tf_ssb_connection_get_id(connection, id, sizeof(id)))
 	{
-		int32_t sequence = 0;
-		tf_ssb_db_get_latest_message_by_author(ssb, id, &sequence, NULL, 0);
-		uv_mutex_lock(&work->ebt->mutex);
-		_ebt_add_to_clock(work, id, sequence, true, true);
-		uv_mutex_unlock(&work->ebt->mutex);
+		if (!_is_blocked(ssb, id))
+		{
+			int32_t sequence = 0;
+			tf_ssb_db_get_latest_message_by_author(ssb, id, &sequence, NULL, 0);
+			uv_mutex_lock(&work->ebt->mutex);
+			_ebt_add_to_clock(work, id, sequence, true, true);
+			uv_mutex_unlock(&work->ebt->mutex);
+		}
 	}
 
 	/* Also respond with what we know about all requested identities. */
@@ -287,7 +301,10 @@ static void _tf_ssb_ebt_get_send_clock_work(tf_ssb_connection_t* connection, voi
 	{
 		for (int i = 0; i < requested_count; i++)
 		{
-			tf_ssb_db_get_latest_message_by_author(ssb, requested[i].id, &requested[i].value, NULL, 0);
+			if (!_is_blocked(ssb, requested[i].id))
+			{
+				tf_ssb_db_get_latest_message_by_author(ssb, requested[i].id, &requested[i].value, NULL, 0);
+			}
 		}
 
 		uv_mutex_lock(&work->ebt->mutex);
diff --git a/src/ssb.rpc.c b/src/ssb.rpc.c
index b874015b..4ffe6ddd 100644
--- a/src/ssb.rpc.c
+++ b/src/ssb.rpc.c
@@ -155,7 +155,7 @@ static void _tf_ssb_rpc_blobs_has_work(tf_ssb_connection_t* connection, void* us
 	blobs_has_work_t* work = user_data;
 	tf_ssb_t* ssb = tf_ssb_connection_get_ssb(connection);
 	sqlite3* db = tf_ssb_acquire_db_reader(ssb);
-	work->found = tf_ssb_db_blob_has(db, work->id);
+	work->found = tf_ssb_db_blob_has(db, work->id) && !tf_ssb_db_is_blocked(db, work->id);
 	tf_ssb_release_db_reader(ssb, db);
 }
 
diff --git a/src/ssb.tests.c b/src/ssb.tests.c
index 6c23b393..cb629f97 100644
--- a/src/ssb.tests.c
+++ b/src/ssb.tests.c
@@ -1905,11 +1905,18 @@ void tf_ssb_test_blocks(const tf_test_options_t* options)
 
 	sqlite3* db = tf_ssb_acquire_db_writer(ssb);
 	tf_ssb_db_add_block(db, message_id);
+	assert(tf_ssb_db_is_blocked(db, message_id));
+	/* Blocked already, because the blocked message references it. */
+	assert(tf_ssb_db_is_blocked(db, blob_id));
 	tf_ssb_db_add_block(db, blob_id);
 	tf_ssb_db_add_block(db, id);
+	assert(tf_ssb_db_is_blocked(db, id));
 	tf_ssb_db_remove_block(db, blob_id);
 	tf_ssb_db_remove_block(db, message_id);
 	tf_ssb_db_remove_block(db, id);
+	assert(!tf_ssb_db_is_blocked(db, message_id));
+	assert(!tf_ssb_db_is_blocked(db, blob_id));
+	assert(!tf_ssb_db_is_blocked(db, id));
 	tf_ssb_release_db_writer(ssb, db);
 
 	tf_ssb_destroy(ssb);