Background:Deficits in knowledge regarding identification and treatment of common mental disorders (CMD) and stigmatizing attitudes towards CMDs exist among primary care physicians in India.Objectives:We aimed to assess the gain in knowledge of CMDs among primary health centre (PHC) doctors, after they underwent training in the identification and treatment of CMDs, and to assess the relationship between the gain in knowledge and demographic variables. We also assessed attitudes towards depression among PHC doctors who underwent training.Methods:We assessed knowledge of CMDs among 38 PHC doctors before and after training using a multiple-choice questionnaire (MCQ). The training session included didactic teaching and case-based discussions.Results:The post-test mean score was significantly higher compared to the pre-test mean score (P < 0.0001), indicative of a significant mean gain in knowledge of CMDs among PHC doctors following training. Significant improvements were noted on the questions assessing identification of CMDs, knowledge of depressive symptoms and identification of panic attacks, post-training (all P < 0.05). Participants with lower pre-test scores had greater improvements in knowledge post-training. Around half of the PHC doctors endorsed negative attitudes towards depression.Conclusions:We demonstrated the efficacy of a training programme for PHC doctors in improving their knowledge of CMDs. Stigmatizing attitudes towards depression were present among around half the PHC doctors even after the training. This has implications for the strategy of integrating mental healthcare into primary care, with the overall goal of reducing the treatment gap for CMDs.