A family tree of 118 members with five members found to have juvenile polyposis-adenomatous change and four juvenile polyposis-adenomatous-carcinomatous change is presented. All the patients developed bleeding per rectum between 10 and 17 years of age. Four members died of colonic malignancy between 30 and 55 years of age. Colonoscopy in five living members revealed typical juvenile polyps throughout the whole length of the colon and atypical large lobulated polyps containing adenomatous change in juvenile polyps in the rectosigmoid area. An autosomal dominant mode of transmission was evident on analysis of the pedigree. Gastric hyperplastic polyps were present in three of the five living members. Familial juvenile polyposis may have the potential to progress into adenoma-carcinoma sequence and is not always a benign disorder. Colonoscopic surveillance should be done to detect adenomatous change if any member of the juvenile polyposis family develops colonic malignancy.