Background: The presence of a family history implies an increased risk for developing colorectal cancer (CRC), and may require a different screening strategy. The aim of this study was to evaluate lesions found during colonoscopies of patients that had a family history of CRC. Material and methods: A retrospective study was conducted that included consecutive colonoscopies performed on patients with a family history of CRC at a referral center within the period from April 2000 to January 2012. The colonoscopic findings were analyzed in relation to sex, age, and the presence or absence of symptoms. Results: Data from 3,792 colonoscopies were collected. The mean age of the patients was 53.14 years (SD 12.22), and 57.4% were women. Colonoscopy was normal in 71.7% of the cases, with hyperplastic polyps being detected in 7.1%, and adenomatous polyps in 19.8% (39.4% of them were high risk). There was a 1.5% presence of adenocarcinomas in the subjects. Polyps and CRC were predominant in men (P=.001 and P=.027, respectively) and there was a linear increase with age. Symptomatic patients had a higher CRC detection rate (P