OBJECTIVE: To conduct a two-stage epidemiological survey in order to measure the prevalence rate of major depressive disorder in girls 12-19 years of age and to relate it to age. SUBJECTS AND METHODS: The Beck Depression Inventory (BDI) questionnaire was administered to 1,107 girls from 3 elementary and 3 secondary schools in Khartoum, Sudan, 272 of whom were selected for intensive interviews. RESULTS: The estimated prevalence of major depressive disorder for the population was 4.2%. Using a cutoff point of 15 on a short BDI, 11% of the adolescent girls reported severe depression. The BDI scores increased with age. A proportion of girls interviewed reported depressive symptoms which did not meet the criteria of Diagnostic and Statistical Manual IV (DSM-IV) for major depressive disorder, and the estimated prevalence of this 'partial syndrome' was 8.6%. CONCLUSION: The findings indicate a high rate of depression. Considering the fact that none of the girls who were identified with major depression reported to the health system, a surveillance system is recommended to identify depression among adolescent girls. Copyright 2003 S. Karger AG, Basel