Author(s): M. Malaiappan BACKGROUND Tuberculosis ranks alongside Human Immunodeficiency Virus as a leading cause of death worldwide.1,2 Psychiatric disorders in chronic medical illnesses have been found to be associated with poor compliance in previous studies. Poor compliance in tuberculosis can have drastic consequences including emergence of drug resistance.1,2,3,4,5 In this study, we have attempted to study the prevalence of psychiatric disorders in tuberculosis at a tertiary care centre in Chennai. The objectives of the study were- 1. To assess the prevalence of psychiatric illnesses in people undergoing treatment for tuberculosis. 2. To assess the association between psychiatric comorbidity and different socio-demographic factors (age, gender, education) and tuberculosis disease related factors. 3. To assess the relationship between psychiatric comorbidity and negative behavioural factors like history of defaulting. MATERIALS AND METHODS Ours is a cross sectional study conducted at the Department of Thoracic Medicine in Government Kilpauk Medical College, Chennai. A total of 106 patients were interviewed and examined. RESULTS We observed that 63.12% of the patients had at least one psychiatric illness. About 62.6% had depressive disorder. Anxiety disorders were found in 23.5%. We also found significant relationships between the following: male gender and presence of psychiatric illnesses, joint family and presence of psychiatric illnesses, dyspnoea grade 3 or more and presence of psychiatric illnesses, dyspnoea grade 3 or more and severity of depression. CONCLUSION The high prevalence of psychiatric disorders in people with tuberculosis warrants specific screening and management.