Percutaneous endoscopic approaches to cholelithiasis would be facilitated by methods for welding gallbladder tissues. We evaluated the bursting pressure and histologic appearance of canine gallbladder tissue welded with a thulium-holmium-chromium:YAG (THC:YAG) laser producing a 2.15 microns pulsed output. The tissue absorption characteristics at this wavelength as well as the pulsed nature of the output permit tissue welding with limited collateral thermal damage. The THC:YAG is compatible with a flexible fiberoptic delivery system. Bursting strengths of the welded junctions averaged 42 mm Hg, which is above physiologically encountered pressures. Histologic sections of the bonded tissues revealed tissue fusion and limited thermal injury to the surrounding tissue. We feel that THC:YAG laser welding may be a useful technique in the clinical development of percutaneous endoscopic biliary surgery.