Abstract Background The clinical significance of pre-sarcopenia in colorectal cancer obstruction has not yet been described. The present study aimed to determine the short- and long-term oncologic impacts of pre-sarcopenia in obstructive colorectal cancer. Methods We retrospectively analyzed 214 patients with obstructive colon cancer between January 2004 and December 2013. Initial staging computed tomography (CT) scans identified pre-sarcopenia and visceral obesity by measuring the muscle and visceral fat areas at the third lumbar vertebra level. Both short-term postoperative and long-term oncologic outcomes were analyzed. Results Among all 214 patients, 71 (33.2%) were diagnosed with pre-sarcopenia. Pre-sarcopenia had a negative oncologic impact in both disease-free survival (DFS) and overall survival (OS), (hazard ratio [HR] = 1.86, 95% confidence interval [CI] 1.04–3.13, p = 0.037, and HR = 1.92, CI 1.02–3.60, p = 0.043, respectively). Visceral adiposity, body mass index (BMI), and neutrophil-lymphocyte ratio (NLR) did not significantly impact DFS and OS. Conclusion Pre-sarcopenia is a clinical factor significantly associated with OS and DFS but not with short-term complications in obstructive colorectal cancer. In future, prospective studies should incorporate body composition data in patient risk assessments and oncologic prediction tools.