Background: Colorectal carcinoma is thought to be rare among children and young adults among whom presentation is usually at a late stage with poor prognosis. Objective: To review the demography, clinical presentation, morphology, and pathological stage of cases of colorectal carcinomas diagnosed in the children and adults. Methods: This was a retrospective review of cases of histologically diagnosed colorectal carcinoma of patients aged 40 years and below, between 1979 and 2008, using the request cards and hematoxylin and eosin stained slides. Results: Seventy-six (31.5%) of all cases of colorectal carcinoma were seen in patients aged 40 years and below. The mean age at presentation was 31years and the youngest aged 16 years. The male : female ratio was 1.6 : 1. The dominant clinical presentations were bloody diarrhea and rectal bleeding. Fifty-one (67.1%) cases were localized to the rectum, nine (16.1%) cases in the sigmoid colon, and eight (10.5%) cases in the caecum. Adenocarcinoma was the most common histological variant. Mucin-producing tumours were seen in 25 (32.9%) cases. Almost all the patients presented at advanced pathological stage. Conclusion: Colorectal carcinoma is not rare among young Nigerians and it should be suspected when young patients present with chronic bloody diarrhoea. Digital rectal examination should be encouraged as part of clinical examination in this age group too since a large percentage of colorectal carcinomas is within the reach of the examining finger.