Fourteen cases of both palpable and non-palpable breast lesions reported as possible ductal carcinoma in situ (DCIS) on fine-needle biopsy (FNB) over a 12-mo period were retrieved from our files and compared to the subsequent histologic diagnosis. Although a definite cytologic pattern of highly cellular smears with high grade nuclei, dissociation, and background necrosis with microcalcifications emerged for comedo DCIS, it was not possible to differentiate these on cytologic grounds from high grade infiltrating carcinoma with necrosis unless mammographic findings were taken into account. Useful criteria for non-comedo low grade DCIS were high cellularity, low grade nuclei, and architectural features of papillary and three dimensional (3D) fragments, palisade arrangements, and monolayer sheets with punched out glandular lumina. We conclude that FNB has a definite role in the diagnosis of these lesions, with the limitation that invasive malignancy can never be excluded on cytologic criteria alone and clinico-radiological correlation is paramount. Diagn Cytopathol 1996;15:367–373. © 1996 Wiley-Liss, Inc.