It is essential to know the nature of breast lesions before surgery. One of the well-known procedures is the cytologic diagnosis by means of Fine Needle Aspiration (FNA). We planned a prospective comparative study to assess how reliable FNA is for breast masses in our institution. 338 ladies with palpable breast lesions underwent FNA cytology and the results were malignant nature in 89 patients, atypia in 33, atypia suspicion in 24, benign in 171, and insufficient material in 21. Histopathologic examinations of the specimens confirmed that 89 of 89 malignant cytology cases were malignant (100%), 25 of 33 atypia cases were malignant (75%), 9 of 24 atypia suspicion cases were malignant (37%), 12 of 171 benign cases were malignant (7%). Most of the malignant cytology cases consisted of invasive ductal carcinomas (78%). Invasive lobular carcinoma represented suspicious cytology in 42%. FNA is 100% specific and 91% sensitive. Lesions containing rich stroma and fewer cells (lobular, colloidal carcinoma) exhibited mainly suspicious findings. We conclude that FNA is a simple, cheap and safe procedure yielding enough information to diagnose breast masses. It allows possible and accurate treatment options to be explained to the patient before surgery. Suspicious cytology should be confirmed by excisional biopsy because of its high malignant potential. If clinical and mammographic findings supports benign cytology, lesions can be followed up.