¹Ondokuz Mayıs University, Faculty of Veterinary Medicine, Department of Surgery, TR-55200 Atakum/Samsun - TURKEY DOI : 10.9775/kvfd.2019.22636 Atresia coli is sporadically seen in calves and lethal unless intestinal patency is restored through surgery. While there are some reports of surgically corrected animals with atresia coli giving birth to healthy offspring, there is still controversy about treating such cases, since survival is not guaranteed and there is a chance of tainting the herd"s gene pool. This study aims to investigate the efficacy of colonoscopy in cases of atresia coli in determining the atresia type and evaluating the lumen. Nineteen calves of different breeds and sex between the ages of 1 to 15 days were included in the study. Colonoscopy duration, maximum distance of the endoscope from the anus and any discernible changes inside the lumen were recorded for each case. The technique was easy to use, required no anaesthesia or sedation and very informative about the condition of the mucosa. Definitive diagnosis of the atresia type using colonoscopy is not possible unless a complete blind end is seen and iatrogenic damage may be caused during the procedure. We believe its diagnostic use can provide the surgeon with data to select which procedure to use and help with prognosis. Keywords : Atresia coli, Calf, Colonoscopy