Histochemical alterations of lectin binding and keratin distribution in experimental carcinomas of the hamster cheek pouch were obtained following cryotreatment. Cryotreated carcinoma cells showed a characteristic reduction in lectin binding and keratin staining shortly following cryosurgery. Tumor tissue, on the 2nd and 3rd days after cryotreatment, displayed destruction and necrosis with almost a complete loss of lectin binding and keratin staining. The remaining neoplastic cells located in the deeper layer showed positive reaction for both lectin binding and keratin, which is indicative of tumor recurrence. Histochemical staining of lectin binding and keratin proteins were useful markers in cryotreated tumor cells to identify either destruction and necrosis or vital activity of neoplastic growth.