A 13-year (1990–2003) retrospective study was carried out to investigate the occurrence of cystic echinococcosis (CE) in patients at Wasso hospital in Ngorongoro district, Tanzania. Hospitalization records were reviewed and confirmed cases of CE were classified according to ward of residence, age, sex, cyst location and type. A total of 171 hydatidosis patients were diagnosed and operated giving an average of 13 cases per year, equivalent to approximately 10 cases per 100 000 people per year. Cystic echinococcosis affected more females (59.1%) than males (40.9%). A significantly higher number of CE cases were recorded in individuals <30 years of age (22.8–30.4%) than in those >30 years of age (2.3–9.4%) (P < 0.05). High proportion of CE (81.5%) occurred in the liver than in other sites, and more females had higher hepatic cysts (47.4%) than males (31.0%). Solitary cysts and single organ involvement were noted in 81.5% cases and multiple cysts in 18.5% cases. Higher multiple organ infections (14.1%) and cyst recurrences (5.3%) were also recorded in females. Orgosorok ward had the highest number (18.7%) of CE cases, while Nainokanoka had the lowest (1.2%). It was concluded that CE infection occurs frequently in humans in Ngorongoro district and female and youths are those most affected. These findings merit for more extensive epidemiological investigations of CE in human to better determine the prevalence, economic impact and risk factors for the disease in this district and other areas of Tanzania.