diff --git a/src/bson.c b/src/bson.c
index 7364979b..72796c79 100644
--- a/src/bson.c
+++ b/src/bson.c
@@ -1393,6 +1393,12 @@ void phongo_zval_to_bson(zval *data, php_phongo_bson_flags_t flags, bson_t *bson
 					}
 				}
 
+				if (strlen(ZSTR_VAL(string_key)) != ZSTR_LEN(string_key)) {
+					phongo_throw_exception(PHONGO_ERROR_UNEXPECTED_VALUE TSRMLS_CC, "BSON keys cannot contain null bytes. Unexpected null byte after \"%s\".", ZSTR_VAL(string_key));
+
+					return;
+				}
+
 				if (flags & PHONGO_BSON_ADD_ID) {
 					if (!strcmp(ZSTR_VAL(string_key), "_id")) {
 						flags &= ~PHONGO_BSON_ADD_ID;
@@ -1439,6 +1445,12 @@ void phongo_zval_to_bson(zval *data, php_phongo_bson_flags_t flags, bson_t *bson
 				}
 			}
 
+			if (strlen(string_key) != string_key_len - 1) {
+				phongo_throw_exception(PHONGO_ERROR_UNEXPECTED_VALUE TSRMLS_CC, "BSON keys cannot contain null bytes. Unexpected null byte after \"%s\".", ZSTR_VAL(string_key));
+
+				return;
+			}
+
 			if (flags & PHONGO_BSON_ADD_ID) {
 				if (!strcmp(string_key, "_id")) {
 					flags &= ~PHONGO_BSON_ADD_ID;
diff --git a/tests/bson/bson-fromPHP-006.phpt b/tests/bson/bson-fromPHP-006.phpt
index e68b2bd7..b48a9c3c 100644
--- a/tests/bson/bson-fromPHP-006.phpt
+++ b/tests/bson/bson-fromPHP-006.phpt
@@ -6,13 +6,19 @@ BSON\fromPHP(): PHP documents with null bytes in field name
 require_once __DIR__ . '/../utils/tools.php';
 
 echo "\nTesting array with one leading null byte in field name\n";
-hex_dump(fromPHP(["\0" => 1]));
+echo throws(function() {
+    fromPHP(["\0" => 1]);
+}, 'MongoDB\Driver\Exception\UnexpectedValueException'), "\n";
 
 echo "\nTesting array with one trailing null byte in field name\n";
-hex_dump(fromPHP(["a\0" => 1]));
+echo throws(function() {
+    fromPHP(["a\0" => 1]);
+}, 'MongoDB\Driver\Exception\UnexpectedValueException'), "\n";
 
 echo "\nTesting array with multiple null bytes in field name\n";
-hex_dump(fromPHP(["\0\0\0" => 1]));
+echo throws(function() {
+    fromPHP(["\0\0\0" => 1]);
+}, 'MongoDB\Driver\Exception\UnexpectedValueException'), "\n";
 
 /* Per PHPC-884, field names with a leading null byte are ignored when encoding
  * a document from an object's property hash table, since PHP uses leading bytes
@@ -21,7 +27,9 @@ echo "\nTesting object with one leading null byte in field name\n";
 hex_dump(fromPHP((object) ["\0" => 1]));
 
 echo "\nTesting object with one trailing null byte in field name\n";
-hex_dump(fromPHP((object) ["a\0" => 1]));
+echo throws(function() {
+    fromPHP((object) ["a\0" => 1]);
+}, 'MongoDB\Driver\Exception\UnexpectedValueException'), "\n";
 
 echo "\nTesting object with multiple null bytes in field name\n";
 hex_dump(fromPHP((object) ["\0\0\0" => 1]));
@@ -31,19 +39,23 @@ hex_dump(fromPHP((object) ["\0\0\0" => 1]));
 <?php exit(0); ?>
 --EXPECT--
 Testing array with one leading null byte in field name
-     0 : 0b 00 00 00 10 00 01 00 00 00 00                 [...........]
+OK: Got MongoDB\Driver\Exception\UnexpectedValueException
+BSON keys cannot contain null bytes. Unexpected null byte after "".
 
 Testing array with one trailing null byte in field name
-     0 : 0c 00 00 00 10 61 00 01 00 00 00 00              [.....a......]
+OK: Got MongoDB\Driver\Exception\UnexpectedValueException
+BSON keys cannot contain null bytes. Unexpected null byte after "a".
 
 Testing array with multiple null bytes in field name
-     0 : 0b 00 00 00 10 00 01 00 00 00 00                 [...........]
+OK: Got MongoDB\Driver\Exception\UnexpectedValueException
+BSON keys cannot contain null bytes. Unexpected null byte after "".
 
 Testing object with one leading null byte in field name
      0 : 05 00 00 00 00                                   [.....]
 
 Testing object with one trailing null byte in field name
-     0 : 0c 00 00 00 10 61 00 01 00 00 00 00              [.....a......]
+OK: Got MongoDB\Driver\Exception\UnexpectedValueException
+BSON keys cannot contain null bytes. Unexpected null byte after "a".
 
 Testing object with multiple null bytes in field name
      0 : 05 00 00 00 00                                   [.....]