The utility of transserosal photoplethysmographic pulse oximetry (PO) to assess intestinal viability intraoperatively was evaluated using an experimental canine model. Comparisons of PO were made with continuous-wave Doppler ultrasound (CWDU) and fluorescein (FL) using histopathologic examination for control. Clinical examination estimates were included for reference. Four 20 cm portions of small bowel from each of four dogs were made ischemic by mesenteric ligation. Thus 320 individual 1 cm bowel segments were studied by means of PO, CWDU, FL, and control histologic grading for ischemia. Statistical analysis revealed no significant differences, with PO matching CWDU and FL in intraoperative assessment of small bowel viability. PO, which is readily available in most operating rooms, is a simpler method than CWDU or FL for assessing intestinal viability. This technique is operator independent, easy to interpret and repeat, and is well tolerated. PO is the preferred alternative for objective intraoperative assessment of intestinal viability.