diff --git a/CHANGELOG.md b/CHANGELOG.md
index b6e6ddca..c25a05d4 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,6 +3,7 @@ Template:
 
 Next
 ---------------------
+- [Fix a regression in `cbor_serialize_alloc` that caused serialization of zero-length strings and bytestrings or byte/strings with zero-length chunks to fail](https://github.com/PJK/libcbor/pull/260) (discovered by [martelletto](https://github.com/martelletto))
 
 0.10.0 (2022-12-29)
 ---------------------
diff --git a/src/cbor/serialization.c b/src/cbor/serialization.c
index e3bb7df5..40f4c531 100644
--- a/src/cbor/serialization.c
+++ b/src/cbor/serialization.c
@@ -74,11 +74,16 @@ size_t cbor_serialized_size(const cbor_item_t *item) {
         case CBOR_INT_64:
           return 9;
       }
+    // Note: We do not _cbor_safe_signaling_add zero-length definite strings,
+    // they would cause zeroes to propagate. All other items are at least one
+    // byte.
     case CBOR_TYPE_BYTESTRING: {
       if (cbor_bytestring_is_definite(item)) {
-        return _cbor_safe_signaling_add(
-            _cbor_encoded_header_size(cbor_bytestring_length(item)),
-            cbor_bytestring_length(item));
+        size_t header_size =
+            _cbor_encoded_header_size(cbor_bytestring_length(item));
+        if (cbor_bytestring_length(item) == 0) return header_size;
+        return _cbor_safe_signaling_add(header_size,
+                                        cbor_bytestring_length(item));
       }
       size_t indef_bytestring_size = 2;  // Leading byte + break
       cbor_item_t **chunks = cbor_bytestring_chunks_handle(item);
@@ -90,9 +95,10 @@ size_t cbor_serialized_size(const cbor_item_t *item) {
     }
     case CBOR_TYPE_STRING: {
       if (cbor_string_is_definite(item)) {
-        return _cbor_safe_signaling_add(
-            _cbor_encoded_header_size(cbor_string_length(item)),
-            cbor_string_length(item));
+        size_t header_size =
+            _cbor_encoded_header_size(cbor_string_length(item));
+        if (cbor_string_length(item) == 0) return header_size;
+        return _cbor_safe_signaling_add(header_size, cbor_string_length(item));
       }
       size_t indef_string_size = 2;  // Leading byte + break
       cbor_item_t **chunks = cbor_string_chunks_handle(item);
diff --git a/test/cbor_serialize_test.c b/test/cbor_serialize_test.c
index a0a3691a..b42744ab 100644
--- a/test/cbor_serialize_test.c
+++ b/test/cbor_serialize_test.c
@@ -505,6 +505,7 @@ static void test_auto_serialize_too_large(void **_CBOR_UNUSED(_state)) {
 
   // Pretend the chunk is huge
   chunk->metadata.string_metadata.length = SIZE_MAX;
+  assert_true(SIZE_MAX + 2 == 1);
   assert_int_equal(cbor_serialized_size(item), 0);
   unsigned char *output;
   size_t output_size;
@@ -531,6 +532,104 @@ static void test_auto_serialize_alloc_fail(void **_CBOR_UNUSED(_state)) {
   cbor_decref(&item);
 }
 
+static void test_auto_serialize_zero_len_bytestring(
+    void **_CBOR_UNUSED(_state)) {
+  cbor_item_t *item = cbor_build_bytestring((cbor_data) "", 0);
+
+  unsigned char *output;
+  assert_int_equal(cbor_serialize_alloc(item, &output, NULL), 1);
+  assert_memory_equal(output, ((unsigned char[]){0x40}), 1);
+  assert_int_equal(cbor_serialized_size(item), 1);
+  cbor_decref(&item);
+  _cbor_free(output);
+}
+
+static void test_auto_serialize_zero_len_string(void **_CBOR_UNUSED(_state)) {
+  cbor_item_t *item = cbor_build_string("");
+
+  unsigned char *output;
+  assert_int_equal(cbor_serialize_alloc(item, &output, NULL), 1);
+  assert_memory_equal(output, ((unsigned char[]){0x60}), 1);
+  assert_int_equal(cbor_serialized_size(item), 1);
+  cbor_decref(&item);
+  _cbor_free(output);
+}
+
+static void test_auto_serialize_zero_len_bytestring_chunk(
+    void **_CBOR_UNUSED(_state)) {
+  cbor_item_t *item = cbor_new_indefinite_bytestring();
+
+  assert_true(cbor_bytestring_add_chunk(
+      item, cbor_move(cbor_build_bytestring((cbor_data) "", 0))));
+
+  unsigned char *output;
+  assert_int_equal(cbor_serialize_alloc(item, &output, NULL), 3);
+  assert_memory_equal(output, ((unsigned char[]){0x5f, 0x40, 0xff}), 3);
+  assert_int_equal(cbor_serialized_size(item), 3);
+  cbor_decref(&item);
+  _cbor_free(output);
+}
+
+static void test_auto_serialize_zero_len_string_chunk(
+    void **_CBOR_UNUSED(_state)) {
+  cbor_item_t *item = cbor_new_indefinite_string();
+
+  assert_true(cbor_string_add_chunk(item, cbor_move(cbor_build_string(""))));
+
+  unsigned char *output;
+  assert_int_equal(cbor_serialize_alloc(item, &output, NULL), 3);
+  assert_memory_equal(output, ((unsigned char[]){0x7f, 0x60, 0xff}), 3);
+  assert_int_equal(cbor_serialized_size(item), 3);
+  cbor_decref(&item);
+  _cbor_free(output);
+}
+
+static void test_auto_serialize_zero_len_array(void **_CBOR_UNUSED(_state)) {
+  cbor_item_t *item = cbor_new_definite_array(0);
+
+  unsigned char *output;
+  assert_int_equal(cbor_serialize_alloc(item, &output, NULL), 1);
+  assert_memory_equal(output, ((unsigned char[]){0x80}), 1);
+  assert_int_equal(cbor_serialized_size(item), 1);
+  cbor_decref(&item);
+  _cbor_free(output);
+}
+
+static void test_auto_serialize_zero_len_indef_array(
+    void **_CBOR_UNUSED(_state)) {
+  cbor_item_t *item = cbor_new_indefinite_array();
+
+  unsigned char *output;
+  assert_int_equal(cbor_serialize_alloc(item, &output, NULL), 2);
+  assert_memory_equal(output, ((unsigned char[]){0x9f, 0xff}), 2);
+  assert_int_equal(cbor_serialized_size(item), 2);
+  cbor_decref(&item);
+  _cbor_free(output);
+}
+
+static void test_auto_serialize_zero_len_map(void **_CBOR_UNUSED(_state)) {
+  cbor_item_t *item = cbor_new_definite_map(0);
+
+  unsigned char *output;
+  assert_int_equal(cbor_serialize_alloc(item, &output, NULL), 1);
+  assert_memory_equal(output, ((unsigned char[]){0xa0}), 1);
+  assert_int_equal(cbor_serialized_size(item), 1);
+  cbor_decref(&item);
+  _cbor_free(output);
+}
+
+static void test_auto_serialize_zero_len_indef_map(
+    void **_CBOR_UNUSED(_state)) {
+  cbor_item_t *item = cbor_new_indefinite_map();
+
+  unsigned char *output;
+  assert_int_equal(cbor_serialize_alloc(item, &output, NULL), 2);
+  assert_memory_equal(output, ((unsigned char[]){0xbf, 0xff}), 2);
+  assert_int_equal(cbor_serialized_size(item), 2);
+  cbor_decref(&item);
+  _cbor_free(output);
+}
+
 int main(void) {
   const struct CMUnitTest tests[] = {
       cmocka_unit_test(test_serialize_uint8_embed),
@@ -570,6 +669,14 @@ int main(void) {
       cmocka_unit_test(test_auto_serialize_no_size),
       cmocka_unit_test(test_auto_serialize_too_large),
       cmocka_unit_test(test_auto_serialize_alloc_fail),
+      cmocka_unit_test(test_auto_serialize_zero_len_bytestring),
+      cmocka_unit_test(test_auto_serialize_zero_len_string),
+      cmocka_unit_test(test_auto_serialize_zero_len_bytestring_chunk),
+      cmocka_unit_test(test_auto_serialize_zero_len_string_chunk),
+      cmocka_unit_test(test_auto_serialize_zero_len_array),
+      cmocka_unit_test(test_auto_serialize_zero_len_indef_array),
+      cmocka_unit_test(test_auto_serialize_zero_len_map),
+      cmocka_unit_test(test_auto_serialize_zero_len_indef_map),
   };
   return cmocka_run_group_tests(tests, NULL, NULL);
 }