Evidence for validity of the diagnostic construct of minor depressive disorder comes primarily from reports on subthreshold depressive states rather than minor depressive disorder per se. We report on the prevalence, impact, and sociodemographic correlates of minor depressive disorder in a developing country setting as further validation of this diagnostic construct. Diagnostic assessment of 1714 adults of an island population in Ethiopia was carried out using the Composite International Diagnostic Interview. The lifetime prevalence of minor depressive disorder was 20.5% (95% confidence interval 18.6, 22.5%). One-third of cases had sought help and expressed suicidal ideation. Being divorced/widowed, middle-aged, and having somatic pain were independently associated with having minor depressive disorder. Only being divorced/widowed was a shared risk factor for both minor depressive disorder and bereavement. Minor depressive disorder seems to be a useful and valid diagnostic construct with particular clinical significance in this and, possibly, similar developing country settings.