Refugees and asylum seekers have a high risk of developing mental health problems and appropriate screening in people from diverse origins remains a challenge. The aim of this study was to validate a structured diagnostic interview, adapted from the Major Depressive Episode (MDE) and Posttraumatic Stress Disorder (PTSD) sections of the Mini International Neuropsychiatric Interview, to detect these disorders among newly arrived asylum seekers. The adapted questionnaire was administered by nurses in a primary care context and its performance was judged against the expert opinion of a mental health specialist. One hundred one subjects were included in the study (mean age: 30; origin: Africa 58%, Europe: 37%, Asia: 5%). MDE and PTSD were diagnosed among 33% and 30% of them respectively. The questionnaire demonstrated moderate sensitivity (MDE: 79%; PTSD: 69%), but high specificity (MDE: 95%; PTSD: 94%). These characteristics remained stable despite cultural differences and use of interpreters. This instrument could be used for systematic screening of MDE and PTSD in refugees from various origins.