The present study aims to clarify the use, in a developing country, of fine-needle aspiration cytology (FNA) instead of open biopsy as a cost-saving, reliable initial diagnostic and management tool for patients with breast mass. A prospective study of 60 patients (71 breast masses) was carried out. The accuracy of physical diagnosis of the mass was compared with that obtained by FNA. The cytological results were analysed with the clinical profiles and pathological results. Physical examination was unreliable for the diagnosis of breast cyst (61.1% positive predictive value, 73.6% negative predictive value), which accounted for 35% of breast masses studied. Aspiration alone determined the diagnosis and management in 39% of masses. For solid breast masses benign cytological results (class I, II) were proved to be reliable (100% positive predictive value), as were malignant cytological results (class V; 100% positive predictive value). Inadequate cytology was reported for five masses (11.9%). Fine-needle aspiration should be routinely performed in all patients with breast masses. This would facilitate prompt diagnosis and treatment in one-third of patients with breast cyst, and the benign cytological result could facilitate definite management in the majority of patients with a low risk of malignancy. This could save cost, time and patient anxiety. For the patients with a high clinical suspicion of breast cancer, the positive cytological result could reliably confirm the diagnosis, while the equivocal result could be combined with mammography or open biopsy. Considering the ease, simplicity and low cost, FNA may be suitable for developing countries where other non-invasive procedures are unavailable or difficult to obtain, and it could replace open biopsy, which is still commonly done.