Background Knowledge of risk factors for recurrence of colorectal adenomas may identify patients who could benefit from individual surveillance strategies. The aim of this study was to identify risk factors for recurrence of colorectal adenomas in a high-risk population. Methods Data were used from a randomized clinical trial that showed no effect of aspirin-calcitriol-calcium treatment on colorectal adenoma recurrence. Patients at high risk of colorectal cancer who had one or more sporadic colorectal adenomas removed during colonoscopy were followed up for 3 years. Independent risk factors associated with recurrence and characteristics of recurrent adenomas were investigated in a generalized linear model. Results After 3 years, the recurrence rate was 25·8 per cent in 427 patients. For younger subjects (aged 50 years or less), the recurrence rate was 19 per cent; 18 of 20 recurrent adenomas were located in the distal part of the colon. For older subjects (aged over 70 years), the recurrence rate was 35 per cent, and 16 of 25 recurrent adenomas were in the proximal colon. Age (odds ratio (OR) 1·04, 95 per cent c.i. 1·01 to 1·07) and number of adenomas (OR 1·27, 1·11 to 1·46) at the time of inclusion in the study were independent risk factors for recurrence. Conclusion In contrast to current guidelines, advanced age is not a reason to discontinue adenoma surveillance in patients with an anticipated live expectancy in which recurrence can arise. Older get more proximal recurrences.