Obsessive compulsive disorder (OCD) is a complex condition characterised by intrusive and distressing thoughts (obsessions) and repetitive behaviours or mental acts (compulsions). The symptoms of OCD cause significant distress and anxiety and can have a debilitating effect on a person’s daily functioning. This article gives an overview of OCD, including its prevalence, aetiology, symptoms and treatment strategies, with the aim of enhancing nurses’ understanding of the condition and its adverse effects on a person’s life. The author also discusses some of the ways in which nurses in any setting can support a person with OCD.