This was a retrospective descriptive study examining responses to the discovery of breast symptoms and the determinants of delay in diagnosis of women with breast cancer. There were 71 women recruited from a medical center Out-Patient Department (OPD) and asked to complete structured questionnaires. On completion of the questionnaires face-to-face interviews were conducted in private. The validity and reliability of the instruments were measured and the correlation coefficients were found to be acceptable (0.64-0.84). Ninety-six percent of the women had self-discovered breast symptoms that included breast lumps, sensation of pain, nipple retraction and nipple secretion. Responses to the discovery were categorized as "worry or fear", "have no unusual sensation", "suspicion", "wait and see", "feel sorry" and "prayer". The time delay between discovery of breast cancer symptoms and pathological diagnosis ranged from less than one week to over six months. Stepwise multiple regressions were computed. The socioeconomic status, education, and Powerful Others Health Locus of Control (PHLC) were the most powerful predictors; together they explained 46% of the variance for diagnostic delay. Also, we found diagnostic delay was significantly correlated with the clinical stage when Sperman's correlation was tested (r = 0.73, P < 0.01). It was indicated that subjects with delayed diagnosis showed a possibility of poorer prognosis at the clinical stage. Nursing implications and strategies are discussed.