Background and Aims: The incremental shuttle walk test (ISWT) is a simple reproducible and non-invasive test for assessing cardiopulmonary function. The maximum oxygen consumption is less than 10 ml/kg/min for ISWT distance of less than 250 m. This study aimed to evaluate the effectiveness of ISWT in predicting morbidity and mortality in elective colorectal oncosurgery and to find the correlation of ISWT with the Duke Activity Status Index (DASI), Borg dyspnoea score, and peak oxygen uptake (VO 2 max)., Methods: This prospective study involved 46 patients aged more than 60 years with American Society of Anesthesiologists physical status I and II undergoing elective colorectal surgery under general anaesthesia with an epidural block. ISWT was conducted preoperatively and patients were monitored for 30 days postoperatively. For a comparative analysis, patients were divided into two groups: group 1- who could walk 250 m and group 2 - could not walk 250m. Categorical data were evaluated using the Chi-square test, while continuous data were evaluated using the Student's t -test. The strength of correlation was determined using Pearson's correlation coefficient., Results: Postoperative complications ( P = 0.001) and lengthy stay in hospital and intensive care unit (P = 0.001) were experienced by all patients who were unable to complete the ISWT distance of 250 m. ISWT distance of 250 m corresponds to a DASI score of 10.5, which is equivalent to a calculated VO 2 max of 14.1ml/kg/min., Conclusion: The ISWT with a cutoff distance of 250 m is a reliable predictor of postoperative morbidity in patients undergoing colorectal oncosurgery., Competing Interests: There are no conflicts of interest., (Copyright: © 2022 Indian Journal of Anaesthesia.)