The indications of Frozen section diagnosis (FS) in surgery due to urologic neoplasia are quite specific, and this explains the fact that they amount to a mere 7.3% of the FSs performed in general hospitals. This also makes the knowledge of their usefulness necessary, and thus we are submitting the present review. Generally speaking, FS is not warranted to identify the nature of a tumoral mass, with the following exceptions: (1) Renal masses of a doubtf ul parenchymal origin, or in the urinary tract: (2) Intesticular neoplasias,when the possibility of a conservative treatment arises; (3) Determination of the presence of a prostate adenocarcinoma in an organ donor with high serum PSA; but even in these circumstances its need is widely controversial. Intraoperative determination of surgical margins is particularly useful in: (1) Partial nephrectomies (it may be limited to inspection after dyeing the margin with Indian ink--bed freezing is very seldom needed); (2) Urethral margins in women with total cystectomies and orthotopic substitution; (3) In partial penectomies (always studying the urethral margin and the cavernosal and spongIosal corpora margins). The study of the nodes is a widely debated issue, and except for those cases in which unexpectedly increased node size is found, systematic FS is indicated neither of the bladder nor of the prostate. The situation regarding penis carcinoma is different, as in the groups with intermediate and high risk of node metastasis, even though there is around 16%-18% of false negatives FS is recommended, particularly of radioisotope-marked sentinel nodes.