Objective: To determine the magnitude of specific mental and behavioural disorders in children in Butajira, southern Ethiopia. Design: A cross-sectional survey. Setting: Butajira district, southern Ethiopia. Subjects: Amharic version of the diagnostic instrument for children and adolescents was used to interview parents of 1477 children. Results: Of the surveyed children 3.5% had at least one or more mental or behavioural disorders. The most frequent diagnoses were anxiety disorders (1.6%), attention deficit hyperactivity disorder (1.5 %) and disruptive behaviour disorders (1.5 %). Mood disorders (I %) and elimination disorders (0.8%) were relatively less common. Conclusion: The study shows that specific mental and behavioural disorders in these children are significant public health problems.