Spontaneous or expressible nipple discharge may occur in palpable and nonpalpable breast lesions. The aim of the study was to evaluate the sensitivity and specificity of nipple discharge cytology in palpable and nonpalpable breast lesions. One hundred and seventy-four nipple discharge specimens were reviewed, of which 82 had corresponding surgical pathology, including 34 palpable breast lesions and 48 nonpalpable breast lesions. There was good correlation between nipple discharge cytology and concomitant fine needle aspiration (FNA) cytology. Nipple discharge cytology is as specific as concomitant FNA cytology but is slightly less sensitive in detecting papillomas or malignant lesions. The sensitivity and specificity of the nonpalpable and palpable breast lesions were similar. Nipple discharge cytology is very helpful in detecting an underlying breast lesion even if the case has no palpable mass in the breast.