diff --git a/psycopg/green.c b/psycopg/green.c
index 8e5ec1be..2f35d9f6 100644
--- a/psycopg/green.c
+++ b/psycopg/green.c
@@ -202,6 +202,7 @@ end:
 static void
 psyco_panic_cancel(connectionObject *conn)
 {
+    PGresult *res;
     PyObject *etype, *evalue, *etb;
     char errbuf[256];
 
@@ -229,6 +230,12 @@ psyco_panic_cancel(connectionObject *conn)
         goto exit;
     }
 
+    /* we must clear the result or we get "another command is already in
+     * progress" */
+    if (NULL != (res = pq_get_last_result(conn))) {
+        PQclear(res);
+    }
+
 exit:
     /* restore the exception. If no exception was set at function begin, don't
      * clobber one that may have been set here. */
diff --git a/sandbox/test_green_error.py b/sandbox/test_green_error.py
index 23a247b5..7d17cf74 100644
--- a/sandbox/test_green_error.py
+++ b/sandbox/test_green_error.py
@@ -42,7 +42,15 @@ signal.signal(signal.SIGHUP, handler)
 conn = psycopg2.connect(DSN)
 curs = conn.cursor()
 print "PID", os.getpid()
-curs.execute("select pg_sleep(1000)")
+try:
+    curs.execute("select pg_sleep(1000)")
+except BaseException, e:
+    print "got exception:", e.__class__.__name__, e
+
+conn.rollback()
+curs.execute("select 1")
+print curs.fetchone()
+
 
 # You can unplug the network cable etc. here.
 # Kill -HUP will raise an exception in the callback.