Antenatal depressive disorders are serious health problems and pose multiple dangers to both the mother and her fetus, however, not given due attention. They are found with significantly higher prevalence rates in low income countries and associated with socio-economic and socio-cultural factors predominantly. The main objective of this study was to assess the prevalence of antenatal depressive disorders and associated factors among Adama Hospital Antenatal clinic attendants. A hospital based cross sectional study was conducted from March 1st to April 21st, 2011 at Adama Hospital, Adama, Ethiopia. About 231 pregnant women were interviewed using systematic sampling method. Pretested Beck Depression Inventory (BDI) structured questionnaire was used to collect data. The presence of depressive disorders was explained by the sum of BDI items scored 21 and above. And, data entry was done by SPSS version 15 and analyzed using logistic regression. 68, CI(3.61, 142.33] were found to have strong association with depressive disorders. The prevalence of antenatal depressive disorders was high at the study area. Psychosocial factors, economic problems and obstetric features were significantly associated with maternal depressive disorder. Adama Hospital should integrate mental health service with existing antenatal clinic service. In addition, screening of antenatal care (ANC) attendants for potential risk factors of antenatal depressive disorders could be crucial to hamper the impending dangers through early detection.