BackgroundAnastomotic dehiscence (AD) is the most feared complication following colonic and rectal anastomosis. Multiple attempts have been made to correlate the levels of biomarkers to the risk of AD. This study attempts to compare C‐reactive protein (CRP), procalcitonin (PCT) and neutrophil‐to‐lymphocyte ratio (NLR) as predictors of AD.MethodThis case‐controlled study collected data on patients undergoing colonic and rectal anastomosis over an 18‐month period. Levels of CRP, PCT and NLR were recorded daily for the first 5 days post‐operatively. These results were then compared between those who developed AD and those who did not.ResultsA total of 136 patients were included; 11 (8.1%) patients developed AD. CRP and NLR were useful predictors of AD with an area under the curve of 0.81 and 0.78 on post‐operative day 4. PCT was not found to be raised significantly higher in patients who developed AD compared to those who did not.ConclusionCRP and NLR are useful predictors of AD. PCT is not a useful predictor of AD.