Payment Address
Blue Cross and Blue Shield of Illinois
P.O. Box ZZ
Chicago, IL 60690-3690

Membership Address
Blue Cross and Blue Shield of Illinois
P.O. Box 1637
Chicago, IL 60690-9859

Claims Address
Blue Cross and Blue Shield of Illinois
P.O. Box 1364
Chicago, IL 60690-1364

Members First
1-888-788-4184
Members First

Medicare
1-800-633-4227
Medicare

Blue Cross Blue Shield of Illinois Customer Service
1-800-624-1723