PURPOSE: The aim of this study was to evaluate the prognostic significance of the breast volume in primary breast cancer patients with the same T stage. METHODS: The study population consisted of 358 patients with T1 and T2 primary breast cancer, who underwent preoperative mammography and surgery in our institution from March 1992 to December 2006. The patients were divided into three groups based on the calculated breast volume as the following: Group A: <285 cc (n=117), Group B: 285-460 cc (n=121) and Group C: > or =460 cc (n=120). Overall survival (OS) and disease free survival (DFS) of the patients in the three groups in each T stage were analyzed. RESULTS: The mean age was 46.3 years (age range, 22-85 years) and the mean calculated breast volume was 403.1 cc (volume range, 94-1,231 cc). As the age of patients was increased, the breast volume was increased (r=0.184, p<0.001). With a mean follow up period of 80.8 months, there was no significant difference in DFS or OS among patients in Groups A, B, and C (p>0.05). For patients with T1 stage disease, Group A patients showed the highest DFS and OS, and patients in Group C showed the lowest DFS and OS; however, the difference was not statistically significant (p>0.05). For patients with T2 disease, patients in Group C showed the highest DFS and OS, though the difference with the two other groups did not have statistical significance (p>0.05). CONCLUSION: The breast volume was not a significant predictor of DFS and OS for patients with T1 and T2 breast cancer. However it should be noted that this was the first study to evaluate the correlation between breast volume and survival in breast cancer patients.