PURPOSE OF REVIEW: We aimed to investigate the recent understanding of the frequent coexistence of obsessive-compulsive disorder (OCD) and major depression (MDD), exploring both clinical and mechanistic perspectives. Our focus was on deriving conclusions with therapeutic implications. RECENT FINDINGS: While biological factors contribute to the development of OCD-MDD, the comorbidity seems to be primarily induced by the convergence of symptoms that complicate the course of OCD. Tailored cognitive-behavioral therapy programs, specifically addressing MDD, alongside SSRI medication, may prove beneficial for patients experiencing moderate to severe forms of this comorbidity. The review underscores the significance of comorbidity from both diagnostic and therapeutic perspectives. However, existing research has yet to offer a clear understanding of the underlying mechanisms. Further research in the field, notably coming from network studies, could enrich our practice by helping to target specific dimensions that underly OCD-MDD comorbidity.