Abstract : Obsessive-compulsive disorder (OCD) is a chronic psychiatric illness characterised by unwanted, repeated thoughts (obsessions) and/or the repetition of rituals or activities(compulsions). It has a global lifetime prevalence rate of 1.5 percent for women and 1.0 percent for men. Aim: To assess the biological and psychosocial factors of a person with OCD and to provide appropriate psychotherapy to the client. A single case study design was carried out with the case of obsessive-compulsive disorder. Post intervention showed a significant reduction of OCD and depressive symptoms. Exposure response prevention (ERP) has been shown to be effective in treating OCD in this case, as evidenced by the post-intervention reduction in OCD symptoms. Implication: ERP is effective guideline for the practitioners to manage OCD symptoms, which is evident from the current case study.