This study assessed patient awareness and use—as well as obstacles to use—of HMO- and community-based psychosocial support services designed for cancer patients. Participants were a randomly selected group of patients from a large Northwest HMO, with breast (N=145), prostate (N=151), or colon cancer (N=72), and their oncology and urology providers (N=29). Patient awareness was highest for HMO-based services (68–90%) and lower for community- (33%) or Internet-based (10–14%) services, and use rates were low across all services (range 2–8%). Providers reported referring 70% of their patients to HMO cancer support services, but their estimates of actual patient use of these services (40%) were inflated. Providers reported few barriers to referring patients to support services. The most commonly reported patient barriers to using such services were already having adequate support, lack of awareness of the service, and lack of provider referral. Results of regression analyses suggest that education, physician referral, social support, and spirituality may be important influences on use of cancer support services. This study takes a first step toward understanding patient use of existing cancer support services and suggests ways to increase participation in these services. Copyright © 2001 John Wiley & Sons, Ltd.