The aim of this study was to evaluate the clinical and pathological features of breast cancer patients with bilateral breast cancer and to assess the impact of the second breast cancer on their prognosis. Thirty six breast cancer patients with bilateral (metasynchronous) cancer were treated in Greatpoland Cancer Center from 1983 to 1995. It constituted 4.1% of all breast cancer patients treated in those years. 5-year survival rates were compared with clinical data (age, clinical stage, histological diagnosis), methods of treatment and length of interval between occurring of both tumors. Five year survival of patients treated for second breast cancer was 55.6% (20/36), disease-free survived--15/36 (41.7%). 5-year survival rate was greater in group of patients with clinical stage T1 or T2 (69.6%, 16/23) than in group with T3 or T4 (30.8%, 4/13) (p=0.009). In group of 20 patients without nodal involvement (N0) 5 years survived 75.0% of patients (15/20), in group with N1--11.1% (1/9) (p=0.01). Length of interval between both breast tumors influenced 5-year survival rate. In group of patients with interval longer than 5 years, 5-year survival rate was 73.9% (17/23), in group of patients with interval shorter than 2 years--0% (0/6) (p=0.002). No correlations were observed between survival rate and age, histological diagnosis, methods of treatment.