Background Reports on pattern of aneurysms among young people are scanty. These data are important for informing preventive and management strategies. This retrospective study at Kenyatta National Hospital, Nairobi. Kenya describes the pattern of aneurysms among young black Kenyans. Patients and methods Records of in-patients, aged up to 40 years, with a diagnosis of aneurysm between January 1998 and December 2007 were examined for localization, presentation, investigations, comorbidities, age and gender distribution. Data were analyzed by SPSS version 13.0 for Windows, and presented in tables and bar charts. Results One hundred and fifteen files were analyzed. Most frequent site was abdominal aorta (32.2%). Of these, majority (59.4%) were infrarenal. Other commonly affected arteries included thoracic aorta (11.3%), posterior communicating (7.8%), femoral (8.7%), brachial (8.7%), common carotid (6.1%) and internal thoracic (5.2%). They presented as pulsatile, often painful masses, and with pressure symptoms. Diagnosis was confirmed by ultrasound and angiography. Common comorbidities were hypertension, smoking, Human Immunodeficiency Virus infection, alcohol, trauma, and connective tissue disorders. Mean age was 26.1 years and male: female ratio was 2.7:1. Conclusion Aneurysms are not uncommon in young Kenyans. They occur more commonly in males than females, and affect diverse vascular beds. Associated comorbidities comprise non communicable lifestyle factors, infection, inborn conditions and trauma. Lifestyle modification from early in life and control of infections are recommended.