The indications for and limitations of rapid cytology were discussed, and intraoperative cytology in combination with frozen section histology was reviewed. During the past 14 years, intraoperative cytology and frozen section histology were simultaneously performed in 1,987 cases of various diseases and organs. A discrepancy between the cytologic and the frozen section diagnoses was noted in 39 (2.0%) instances, and the combined use of cytology and histology was concluded to be useful for correct intraoperative diagnosis owing to their supplementary effect. A rapid preparation and staining technique for intraoperative cytology was described.