INTRODUCTION: Anastomotic leakage (AL) is one of the most disastrous complications after rectosigmoid cancer operations. The aim of this study is to investigate the effect of the insertion time of circular stapler anvil on assessing the blood supply of the proximal colon segment, and thus to evaluate the prevention of early anastomotic leaks. MATERIAL METHODS: A total of 57 patients were included in the study, 25 patients in group A and 32 patients in group B, respectively. From the beginning of the operation to the time of anvil placement in group A, it was 32.08 (± 7.34) minutes, and in group B it was 92.19 (± 16.63) minutes. None of the patients in group A had AL, and 4 patients in group B had AL. DISCUSSION: Our study shows that the anvil must be placed at the beginning of the dissection to evaluate the anomalies that cause anastomotic leaks. We think that this method increases the reliability of the anastomosis line. Thus, the hospitalization period of the patients was shortened and they returned to their active lives faster. In addition, patients used less antibiotics and they needed less medical treatment.