Objectives. To describe the diarrhoea admissions and the influencing factors in 6 - 60-month-old children at Morogoro Regional Hospital. Design. A retrospective descriptive study of the type of diarrhoea, patient age, home address, nutritional status, diagnosed infection, month of admission, admission duration and outcome. Setting. A hospital-based study: paediatric admissions at Morogoro Regional Hospital. Subjects. All children aged 6 - 60 months admitted to the infectious diseases ward over the 60-month period from May 2006 to April 2011. Results. A total of 4 988 records were extracted, among which the prevalence of diarrhoea was 2 855 (57.2%). Among the 2 855 children with diarrhoea, the majority (2 536 (88.8%)), were 6 - 24 months old, with peak admissions at 7 months and 12 months. District of residence, season, undernutrition and infection were the factors significantly associated (p<0.001) with the age at which children were admitted with diarrhoea. Conclusions. There were increased numbers of admissions for diarrhoea at the ages of 7 months and 12 months, during the dry season and together with diagnosed infection, particularly malaria. However, further study on causes of childhood diarrhoea, given the identified risk factors, may better explain the epidemiology of diarrhoea in Morogoro.