diff --git a/src/MongoDB/WriteConcern.c b/src/MongoDB/WriteConcern.c
index 9af1d10f0..329f008a6 100644
--- a/src/MongoDB/WriteConcern.c
+++ b/src/MongoDB/WriteConcern.c
@@ -56,7 +56,9 @@ PHP_METHOD(WriteConcern, __construct)
 	zval                     *w;
 	long                      wtimeout = 0;
 	zend_bool                 journal = 0;
+	zend_bool                 journal_is_null = 0;
 	zend_bool                 fsync = 0;
+	zend_bool                 fsync_is_null = 0;
 
 	(void)return_value; (void)return_value_ptr; (void)return_value_used;
 
@@ -64,7 +66,7 @@ PHP_METHOD(WriteConcern, __construct)
 	zend_replace_error_handling(EH_THROW, phongo_exception_from_phongo_domain(PHONGO_ERROR_INVALID_ARGUMENT), &error_handling TSRMLS_CC);
 	intern = (php_phongo_writeconcern_t *)zend_object_store_get_object(getThis() TSRMLS_CC);
 
-	if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "z|lbb", &w, &wtimeout, &journal, &fsync) == FAILURE) {
+	if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "z|lb!b!", &w, &wtimeout, &journal, &journal_is_null, &fsync, &fsync_is_null) == FAILURE) {
 		zend_restore_error_handling(&error_handling TSRMLS_CC);
 		return;
 	}
@@ -92,10 +94,14 @@ PHP_METHOD(WriteConcern, __construct)
 
 	switch(ZEND_NUM_ARGS()) {
 		case 4:
-			mongoc_write_concern_set_fsync(intern->write_concern, fsync);
+			if (!fsync_is_null) {
+				mongoc_write_concern_set_fsync(intern->write_concern, fsync);
+			}
 			/* fallthrough */
 		case 3:
-			mongoc_write_concern_set_journal(intern->write_concern, journal);
+			if (!journal_is_null) {
+				mongoc_write_concern_set_journal(intern->write_concern, journal);
+			}
 			/* fallthrough */
 		case 2:
 			if (wtimeout < 0) {
diff --git a/tests/writeConcern/writeconcern-ctor-001.phpt b/tests/writeConcern/writeconcern-ctor-001.phpt
index ee869da98..9280021dc 100644
--- a/tests/writeConcern/writeconcern-ctor-001.phpt
+++ b/tests/writeConcern/writeconcern-ctor-001.phpt
@@ -24,6 +24,10 @@ var_dump(new MongoDB\Driver\WriteConcern("string", 7000, true, true));
 var_dump(new MongoDB\Driver\WriteConcern("string", 8000, true, false));
 var_dump(new MongoDB\Driver\WriteConcern("string", 9000, false, true));
 
+var_dump(new MongoDB\Driver\WriteConcern("string", 10000, null));
+var_dump(new MongoDB\Driver\WriteConcern("string", 11000, null, true));
+var_dump(new MongoDB\Driver\WriteConcern("string", 12000, true, null));
+
 ?>
 ===DONE===
 <?php exit(0); ?>
@@ -172,4 +176,40 @@ object(MongoDB\Driver\WriteConcern)#%d (%d) {
   ["journal"]=>
   bool(false)
 }
+object(MongoDB\Driver\WriteConcern)#%d (%d) {
+  ["w"]=>
+  string(6) "string"
+  ["wmajority"]=>
+  bool(false)
+  ["wtimeout"]=>
+  int(10000)
+  ["fsync"]=>
+  NULL
+  ["journal"]=>
+  NULL
+}
+object(MongoDB\Driver\WriteConcern)#%d (%d) {
+  ["w"]=>
+  string(6) "string"
+  ["wmajority"]=>
+  bool(false)
+  ["wtimeout"]=>
+  int(11000)
+  ["fsync"]=>
+  bool(true)
+  ["journal"]=>
+  NULL
+}
+object(MongoDB\Driver\WriteConcern)#%d (%d) {
+  ["w"]=>
+  string(6) "string"
+  ["wmajority"]=>
+  bool(false)
+  ["wtimeout"]=>
+  int(12000)
+  ["fsync"]=>
+  NULL
+  ["journal"]=>
+  bool(true)
+}
 ===DONE===
diff --git a/tests/writeConcern/writeconcern-getfsync-001.phpt b/tests/writeConcern/writeconcern-getfsync-001.phpt
index 717d45146..0e5011bd1 100644
--- a/tests/writeConcern/writeconcern-getfsync-001.phpt
+++ b/tests/writeConcern/writeconcern-getfsync-001.phpt
@@ -31,6 +31,6 @@ bool(true)
 bool(false)
 bool(true)
 bool(false)
-bool(false)
+NULL
 NULL
 ===DONE===
diff --git a/tests/writeConcern/writeconcern-getjournal-001.phpt b/tests/writeConcern/writeconcern-getjournal-001.phpt
index afb96e465..c3118c124 100644
--- a/tests/writeConcern/writeconcern-getjournal-001.phpt
+++ b/tests/writeConcern/writeconcern-getjournal-001.phpt
@@ -31,6 +31,6 @@ bool(true)
 bool(false)
 bool(true)
 bool(false)
-bool(false)
+NULL
 NULL
 ===DONE===