diff --git a/PGConnection.h b/PGConnection.h
index ef16f53..dd392df 100644
--- a/PGConnection.h
+++ b/PGConnection.h
@@ -20,7 +20,7 @@
 - (void)reset;
 - (PGResult*)executeCommand: (OFConstantString*)command;
 - (PGResult*)executeCommand: (OFConstantString*)command
-		 parameters: (id)firstParameter, ...;
+		 parameters: (id)firstParameter, ... OF_SENTINEL;
 - (PGconn*)PG_connection;
 - (void)insertRow: (OFDictionary*)row
 	intoTable: (OFString*)table;
diff --git a/test.m b/test.m
index a3e354d..18cfa02 100644
--- a/test.m
+++ b/test.m
@@ -34,7 +34,7 @@ OF_APPLICATION_DELEGATE(Test)
 			parameters: @1, @"foo", @"Hallo Welt!", nil];
 	[connection executeCommand: @"INSERT INTO test (id, content, success) "
 				    @"VALUES ($1, $2, $3)"
-			parameters: @2, @2, @YES];
+			parameters: @2, @2, @YES, nil];
 	[connection insertRow: @{ @"content": @"Hallo!", @"name": @"foo" }
 		    intoTable: @"test"];