A stacked card connector (100) adaptor for receiving cards includes a first electrical card connector (1), a second electrical card connector (2) under the first electrical card connector and a retaining member (4) integral with the second insulating housing. The first card connector includes a first insulating housing (12) received a plurality of first terminals (13). The second card connector includes a second insulating housing (22) received a plurality of second terminals (23). The retaining member defines a plurality of slots (41), said first and second terminals partially passing through the slots.