Laser coagulation (LC) by Nd:YAG laser and cryodestruction (CD) by insulated cryoprobe were done in 52 patients with carcinoma of the rectum (LC = 27, CD = 25). The patients were divided into four groups: group I, inoperable rectal carcinoma because of advanced stage of malignancy, severe concomitant disease, old age (LC = 14, CD = 12); group II, patient refused permanent colostomy (LC = 4, CD = 3); group III, polypoid lesion fulfilled the criteria of local excision (LC = 3, CD = 2); group IV, local recurrence after anterior resection (LC = 6, DC = 8). The mean hospital stay was 8.11 +/- 5.6 days for LC and 12.8 +/- 8.7 days for CD (p less than 0.05). For LC minimal or no sedation was needed, but for CD general anesthesia (n = 3) was occasionally necessary. Significant improvement was achieved in 85.18% (n = 23) of cases with LC and 56% (n = 14) of cases with CD (p less than 0.05). Complications after LC were mild (n = 7) to moderate (n = 3) and after CD they were moderate (n = 11) to severe (n = 2). Almost every patient with CD complained of moderate to severe discharge of malodorous necrotic tissue for a period of 2 weeks or more. In groups I, II, and IV patients with LC enjoyed a longer (81.08 +/- 47.48 days) trouble-free period than those with CD (43.3 +/- 13.45 days) (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)