In the Saarland there is a population-based cancer registry, which has collected information about cancer cases over a long period. An important task of population-based cancer registries is the analysis of its data in respect to incidence, mortality and survival of cancer patients. Not all patients who have been diagnosed with cancer die of that disease. In order to evaluate the survival of cancer patients in respect of their particular disease, survival rates are calculated after the determination of the influence of other causes of death. The so-called relative survival rates (calculated for the first five years after diagnosis) are also used in order to evaluate simultaneously the prognostic importance of variables such as sex, age and year of diagnosis. This analysis with data from the cancer registry of the Saarland deals with 9 tumor localizations: stomach, colon, rectum; breast, cervix uteri and corpus uteri; prostate, lung, malignant skin melanoma. In general the 5-year relative survival rates slightly increased when the time period 1972-1976 was compared with 1982-1986. Cancer of the corpus uteri was one exception, in that the relative survival rate was constant over time, and cancer of the cervix uteri was another, in that a decrease of relative survival rate was found, which together with the decreasing incidence might be ascribed to a successful early detection program. There was no significant improvement in the relative survival time for lung or breast cancer patients.