Herein is reported the cytologic features of four cases of cystic neoplasms of the pancreas as seen in fine-needle aspirates. Cytologically, the cases fall into two distinct groups: mucinous cystic neoplasm and serous cystadenoma. The aspirates from the mucinous cystic neoplasms characteristically showed columnar mucus-secreting epithelial cells, some of which were arranged in a papilloglandular pattern, with abundant mucous material in the background. The aspirates from the serous cystadenoma yielded small sheets of cuboidal cells with small nuclei and clear cytoplasm, without a background of mucous material. This cytologic division corresponds closely to the histologic classification proposed by Compagno and Oertel and hence is of prognostic and therapeutic value. The diagnostic challenges confronted by the cytopathologist are (1) to differentiate neoplastic cysts from the inflammatory pseudocysts; (2) to differentiate neoplastic epithelium from the normal epithelium of the bowel and pancreatic ducts; and (3) to differentiate mucinous cystic neoplasms from serous cystadenomas.