Abstract Certain laboratory findings are presented which we think directly relate to the clinical problems of cryosurgery. Our experience in dealing with a variety of neoplasms is recorded. It is our opinion that the majority of skin tumours, benign and malignant, are best treated in this way and the advantages over radiotherapy and conventional excision are pointed out. Cryotherapeutic results on large tumours such as sarcomas and rectal carcinomas we regard as less satisfactory because of technical reasons. Cryoprostatectomy on a highly selected group of patients has produced encouraging results although we would still regard this method of treatment as in its infancy and requiring further assessment. A brief comment is made on 33 cases of benign enlargement and 3 carcinomas of the prostate.