Intraoperative cytology is a practical in-hospital technique that can aid the veterinary surgeon in making rational decisions about the immediate course of therapy. The most important uses for this procedure are to differentiate neoplasia and inflammation, search for evidence of metastatic disease, ensure that surgical biopsies contain representative tissue, and screen for completeness of surgical resection by assessing tissue margins. Although intraoperative cytology cannot replace histopathology, it can provide information that would otherwise be unavailable to the surgeon. Cytology performed during surgery can provide accurate and reliable information but requires an understanding of the cytology of normal and abnormal tissue and a basic knowledge of the expected biologic behavior of neoplastic tissue.