Fourty-five patients, 28 men, 17 women (mean age 73 +/- 18 yrs) with rectal carcinoma underwent palliative endoscopic neodymium YAG laser therapy. Rectal hemorrhage ceased in 89 p. 100 of affected patients after 3 +/- 2 sessions and a normal rectal transit was restored in 80 p. 100 of affected patients after 3 +/- 1 sessions. Total destruction of intraluminal tumor was achieved in 40 p. 100 of patients after 4 +/- 1 sessions. Symptomatic improvement was more frequent in patients in whom total destruction of intraluminal tumor was achieved (p less than 0.01). Stepwise logistic regression selected 2 independent variables capable of predicting tumoral destruction: the kind of surgical contraindication, more often related to cancer extension (p less than 0.001) and a greater tumor length (p less than 0.03) in patients in whom destruction of intraluminal tumor was incomplete. Twenty-eight patients were subsequently treated after palliation was achieved. Cumulative probability of remaining improved at 6 months when treatment was not stopped was 40 p. 100 (confidence limits to 95 p. 100: 23 p. 100-59 p. 100). Five complications occurred, 3 rectovaginal fistulas and 2 stenosis.