Background and goal of study: Older patients are said to be more sensitive to analgesics and to have a higher risk of side effects due to pharmacokinetic changes developing with old age. On account of this many elderly patients with cancer pain are denied adequate analgesic treatment. We compared efficacy and side effects of cancer pain management in different age groups. Methods: From 1994 to April 1996 577 cancer patients were treated in our pain clinic according to WHO-Guidelines. Efficacy and side effects were evaluated for 508 patients (< 65 years=G1: 323 patients, 65-74 years=G2: 127 patients, > 74 years=G3: 58 patients) with a computerised documentation system. Results: 508 patients were treated on 42123 days and revisited on 5572 controls. 30 patients were treated longer than 1 year (G1 21 patients, G2 6 patients, G3 3 patients). 143 patients were treated until death. 286 patients were treated on 19448 days with oral morphine. (G1: 1712 days; G2: 3645 days; G3: 2364 days). Geriatric patients (G3) received significantly higher doses of morphine than younger patients: Adjuvant drugs were given on 81% of treatment days (G1 84%, G2 75%, G3 75%). Incidence and intensity of side effects were not increased in older patients with the exception of urinary disorders. Conclusions: Geriatric patients with cancer pain can be treated as effectively according to WHO-Guidelines as younger patients. In our study patients in the old age group received significantly higher doses of oral morphine. When analgesic drugs are titrated according to individual needs, side effects are not more frequent or severe than in younger patients.