Introduction: Obsessive-compulsive disorder (OCD) is a disabling mental condition. Many studies have shown that OCD patients have cognitive deficits in various aspects of their cognition, which is a worsening factor of symptom severity, a potential endophenotype, insight predictor, and prognostic indicator of OCD. We designed this systematic review to evaluate the clinical efficacy of cognitive rehabilitation in cognitive deficits and symptom severity of patients with OCD following the PRISMA guidelines.
Methods: We searched PubMed, Scopus, ScienceDirect, Google Scholar, and Cochrane Library using the MeSH terms and keywords of ‘cognitive rehabilitation’ and ‘obsessive-compulsive disorder’. The database search identified 200 records of interest, and then 105 duplicates were removed from them. From 95 remaining studies, six articles were eligible for the study and met the inclusion criteria. The six articles described individual RCT studies representing a wide variety of study designs. 
Results: The six included studies investigated the effect of “organizational training”, “cognitive remediation”, “attention splitting” and “goal management training” on cognitive impairments and symptom severity of OCD patients.
There are a small number of studies with different designs and some biases that have examined the effectiveness of cognitive rehabilitation in OCD patients, with conflicting results regarding the effect of cognitive rehabilitation on OCD symptom severity or cognitive deficit. 
Conclusion: According to the results, we cannot conclude about the efficacy of cognitive rehabilitation in adults with OCD. Considering the importance of cognitive deficits in OCD patients, it is necessary to design and conduct standard trials to investigate the role of cognitive rehabilitation in these disorders.