The study reported here was undertaken by the French Federation of Anticancer Institutes. In 1985 results were reported [1] from six participating Institutes on 597 cases of prostate cancer treated exclusively by radiotherapy during the period 1975–1982. In 1986 [2] and 1987 [3] the study was extended to 15 Institutes, including 1110 cases and covering the same period. In 1989 [6], we analyzed 1100 cases from 16 Institutes. The present contribution represents an overview of the results from this study to date. Final conclusions concerning prognostic factors must await the results of a multivariate analysis.