OBJECTIVES: In the UK, anastomotic leak rate after colorectal surgeries has been reported up to 19%. Yet, clinical and economic consequences of anastomotic leak have not been clearly articulated. Our study aims to estimate the clinical/economic burden of anastomotic leak following colorectal surgeries in the UK. METHODS: The Hospital Episode Statistics database was used to identify English National Health Service Trust adult patients undergoing colorectal surgeries between January 2007 and December 2011. Anastomotic leak was identified by re-intervention/diagnosis codes within a 30-day window following colorectal surgery, including re-operation, re-anastomosis, stent, colostomy, image guided drainage, washout procedure, abscess/drainage and diagnosis of generalized (acute) peritonitis. Hospital costs were calculated using Healthcare Resource Group and Department of Health reference index costs. Differences in outcomes between groups were compared using a propensity score matching approach, adjusting for age, gender, admission method, surgery type, comorbidity and medical stabilization.  RESULTS: A total of 131,689 patients received colorectal surgeries (mean age: 65.2±15.4, male: 50.4%). The rate of anastomotic leak following colorectal surgery was 6.4% (8,404 out of 131,689). After propensity score matching by key covariates, Patients with leak (vs. without leak) had higher in-hospital mortality (15.9% (95% CI: 15.2%, 16.7%) vs. 6.2% (95% CI: 5.7%, 6.7%), p<0.001), 30-day readmission rate (19.7% vs. 11.6%, p<0.001), and post-operative infection rate (19.3% vs. 4.5%, p<0.001). The hospitalizations for patients with leak (vs. without leak) were more costly (£9,071±£4,588 vs. £6,420±£2,895, p<0.001) and longer (20±23 vs. 11±13 days, p<0.001). Anastomotic leak resulted in an additional cost of £2651 and an extra LOS of 9 days per patient.   CONCLUSIONS: Our findings underscore the clinical/economic burden of anastomotic leak after colorectal surgeries in the UK. The presence of anastomotic leak was associated with greater mortality, LOS, and costs, highlighting the importance of providing prompt medical attention to minimize the impact of anastomotic leak.