The effects of intensified primary health care were examined in the "Support-Care-Rehabilitation" project conducted in Uppsala county 1993-1997. Intensified primary health care was one part of an individual support intervention and comprised extended information about patients from the specialist clinics, and education and supervision in cancer care for GPs and home care nurses. The aim was to improve the ability of general practitioners and home care nurses to monitor and support cancer patients. A total of 485 newly diagnosed cancer patients were randomized to intensified primary health care or to a control group (standard care). The intervention group showed a marked increase in follow-up contacts. About 90% of intensified primary health care patients reported such contacts, compared to 26% of control patients. The number of days of hospitalization at the specialist clinics for elderly patients (> or = 70 yr.) randomized to the intervention group were 393 less than for elderly controls three months after diagnosis. The conclusion is that intensified primary health care constitutes a cost-effective strategy for enhancing co-operation between home care, primary health care and specialist clinics.