We report pathological characteristics of screen detected breast cancers versus breast cancers diagnosed outside the official breast screening program. The breast cancer screening program was organised in the county of Haute-Vienne and a pathological record was established in the Association de dépistage des cancers du sein (ADCS 87). Three hundred and thirty three cases were recorded in 50 to 74 years-old women who had been screened (74 were interval cancers), six hundred and eighty seven in 50 to 74 years-old women without screening and three hundred and fifteen in women under 50. No difference in ductal carcinoma in situ or histological type was noted but tumor size and lymph node involvement presented significantly more favorable prognosis in screen detected breast cancers. This study confirms the potential benefit of screening in breast cancer.