We investigated the association between mode of breast cancer (Bca) detection and diagnosis delay in a case-series of primary, histologically confirmed Bca patients from Southern Italy. Nine hundred and fifty nine women diagnosed with incident, primary Bca were recruited in two southern Italian regions. We grouped the mode of detection into two categories: Self-Detection (S-D) and Mammography (MG). Diagnosis delay was defined as the time between detection and a histologically confirmed diagnosis of invasive Bca. 20.9% detected Bca with MG while 79.1% had S-D Bca. Women who detected Bca themselves (S-D) were more likely to delay breast cancer diagnosis than women who were diagnosed by a mammography (MG) (OR: 2.0; 95% CI: 1.39-2.87); when considering the model adjusted for health system-related characteristics, the risk increased (OR: 2.13; 95% CI: 1.47-3.09). Our study indicates a disadvantage in terms of diagnostic delay for women who were admitted and treated in community hospitals compared to women admitted and treated in breast health services.