diff --git a/Modules/_sqlite/connection.c b/Modules/_sqlite/connection.c
index 7417791..309b168 100644
--- a/Modules/_sqlite/connection.c
+++ b/Modules/_sqlite/connection.c
@@ -765,6 +765,10 @@
     int narg;
     int rc;
 
+    if (!pysqlite_check_thread(self) || !pysqlite_check_connection(self)) {
+        return NULL;
+    }
+
     if (!PyArg_ParseTupleAndKeywords(args, kwargs, "siO", kwlist,
                                      &name, &narg, &func))
     {
@@ -794,6 +798,10 @@
     static char *kwlist[] = { "name", "n_arg", "aggregate_class", NULL };
     int rc;
 
+    if (!pysqlite_check_thread(self) || !pysqlite_check_connection(self)) {
+        return NULL;
+    }
+
     if (!PyArg_ParseTupleAndKeywords(args, kwargs, "siO:create_aggregate",
                                       kwlist, &name, &n_arg, &aggregate_class)) {
         return NULL;
@@ -884,6 +892,10 @@
     static char *kwlist[] = { "authorizer_callback", NULL };
     int rc;
 
+    if (!pysqlite_check_thread(self) || !pysqlite_check_connection(self)) {
+        return NULL;
+    }
+
     if (!PyArg_ParseTupleAndKeywords(args, kwargs, "O:set_authorizer",
                                       kwlist, &authorizer_cb)) {
         return NULL;
@@ -909,6 +921,10 @@
 
     static char *kwlist[] = { "progress_handler", "n", NULL };
 
+    if (!pysqlite_check_thread(self) || !pysqlite_check_connection(self)) {
+        return NULL;
+    }
+
     if (!PyArg_ParseTupleAndKeywords(args, kwargs, "Oi:set_progress_handler",
                                       kwlist, &progress_handler, &n)) {
         return NULL;
@@ -1020,6 +1036,10 @@
     PyObject* weakref;
     int rc;
 
+    if (!pysqlite_check_thread(self) || !pysqlite_check_connection(self)) {
+        return NULL;
+    }
+
     if (!PyArg_ParseTuple(args, "O", &sql)) {
         return NULL;
     }