Objectives -The aim of this study was to evaluate the histological characteristics of adenomatous polyps (AP), non adenomatous polyps (NAP), and colorectal cancers (CRC) diagnosed in the greater Paris area. Material and methods -Pathologists filled out an identification and histological questionnaire for each biopsy or surgical specimen received between 20/09/02 and 20/12/02, which had at least one colorectal polyp or CRC, taken from a patient of the greater Paris area. Results -The participation rate of pathologists was 73.3%and 10 396 patients with 16 681 lesions were included. Lesions consisted in 1 223 CRC among 1 107 patients, 9 280 AP and 6 178 NAP. Mean age of patients with CRC was 68 years, with at least one AP without CRC 62 years, and with at least one NAP without CRC or AP 58 years. The mean number of polyps per patient was 1.4, and increased with age. Average size of AP was larger than that of NAP and the size increased with age for AP but not NAP. pTNM staging of CRC was: pT0, 1%pT1, 4%pT2, 13%pT3, 63%pT4, 19%N0, 55%N1, 24%N2, 19%Nx, 2%. Conclusion -This study provides detailed data on colorectal polyps and colorectal cancers in the greater Paris region, which does not have a cancer registry. Repeated surveys could be helpful for evaluating the efficacy of screening programs in the general population. Objectives-The aim of this study was to evaluate the histological characteristics of adenomatous polyps (AP), non adenomatous polyps (NAP), and colorectal cancers (CRC) diagnosed in the greater Paris area. Material and methods - pathologists filled out an identification and histological questionnaire for each biopsy or surgical specimen received between 20/09/02 and 20/12/02, which had at least one colorectal polyp or CRC, taken from a patient of the greater Paris area. Results -The participation rate of pathologists was 73.3% and 10 396 patients with 16 681 lesions were included. Lesions consisted in 1 223 CRC among 1 107 patients, 9 280 AP and 6 178 NAP. Mean age of patients with CRC was 68 years with at least one AP without CRC 62 years, and with at least one NAP without CRC or AP 58 years. The mean number of polyps per patient was 1.4, and increased with age. Average size of AP was larger than that of NAP and the size increased with age for AP but not NAP. PTNM staging of CRC was: pT0, 1% pT1, 4% pT2, 13% pT3, 63% pT4, 19% N0, 55% N1, 24% N2, 19% Nx, 2%. Conclusion- This study provides detailed data on colorectal polyps and colorectal cancers in the greater Paris region, which does not have a cancer registry. which repents surveys could be helpful for evaluating the efficacy of screening programs in the general population.