The aim of this retrospective study is to compare the surgical aesthetic outcome and breast cancer (BC) characteristics in patients with BC detected either by opportunistic screening or clinical diagnosis. 262 women undergoing surgery for BC between 2009 and 2012 were included. The following features were compared in the two groups of patients: (1) age at diagnosis; (2) family history of BC; (3) histology type; (4) tumor diameter; (5) local staging, and (6) type of surgical treatment. In 92/262 (35.1%) cases BC was detected by screening and 170/262 (64.9%) had clinical diagnosis. A positive family history and ductal carcinoma in situ diagnosis were more frequent in patients with clinical diagnosis (P = .001 and P < .0001 respectively). Mean maximum diameter of invasive cancers was significantly greater in symptomatic patients (P < .001). Breast conserving surgery was performed in 76/92 (82.6%) patients with screening and 115/170 (67.6%) with clinical diagnosis. Mastectomy was performed in 16/92 (17.4%) patients with screening and 55/170 (32.3%) with clinical diagnosis. Mastectomy was more frequent in patients with clinical diagnosis of BC (P = .010). No significant group differences were found regarding the other features. This study demonstrated that in opportunistic screening, breast conserving surgery may be applied in a higher number of cases compared to patients presenting with clinical diagnosis, thereby improving life quality of these patients.