Endoscopic treatment of rectal villous adenomas with argon and neodymium:yttrium aluminum garnet lasers is reported in 56 patients. Patients treated include 25 who had polyp recurrence after non-laser polyp treatment, 8 who had small sessile polyps that would otherwise require major surgery, and 23 who had contraindications to surgery. Complete tumor ablation was documented over a 3-24-mo follow-up period in 42 of the 56 treated patients. Of the remaining 14 patients, 5 were referred for other therapy because invasive carcinoma developed during treatment, 5 could not be assessed with confidence because of radiation proctitis, and 4 were lost to follow-up. In all patients with symptoms, improvement was noted when 75% of the tumor was destroyed. Treatment was well tolerated with no major complications. The results compare favorably with conventional treatment. Because laser tissue destruction precludes complete histologic evaluation of polyp tissue, laser ablation of polyps should presently be limited to (a) patients with recurrent tumors after previous non-laser treatment who refuse surgery, (b) patients with serious contraindications to surgery, and (c) small benign tumors that would require major surgery.