AbstractObjective  Liver transplantation (LT) is the treatment of choice for end‐stage liver disease. The required immunosuppression increases the risk for developing malignancies. Some viruses play a crucial role. Data on neoplasms of the colon, rectum and anus in LT are limited.Method  A retrospective evaluation of the incidence and clinical course of colorectal and anal malignancies and colonic polyps in a series of 467 consecutive LTs in 402 individuals between 1998 and 2001 was performed. Standard immunosuppression included Tacrolimus, Mycophenolic acid and steroids.Results  During a median follow up of 5.2 years, three colon adenocarcinomas, one EBV associated cecal post‐transplant lymphoproliferative tumour and two HPV associated anal tumours were identified. Pre‐LT colonoscopy was performed in 161 patients (40%), and of 153 evaluable individuals, 53 (34.9%) had polyps. Colonoscopy was performed in 186 patients (46.3%) median 14.8 (range 0.2–77.8) months post‐LT and 55 (29.3%) had polyps. Post‐LT adenomatous polyps were detected in 47.3% of patients with pre‐LT polyps vs 6.7% of patients without pre‐LT polyps (P < 0.001). Patients with alcoholic liver disease had a significantly higher rate of adenoma formation (50.0%vs 11.1%, P < 0.001). No patient died from colorectal/anal malignancy.Conclusion  The incidence of metachronous and new polyp formation in our study is similar to people who are not immunocompromised, but subgroups are at increased risk. Viral‐associated malignancies, including post‐transplant lymphoproliferative disorders and anal cancer, are important entities in the LT population suggesting that complete screening of the colon, rectum and anus including pre‐LT and post‐LT colonoscopy should be utilized.