Background: There is evidence of impairment in the cognitive functioning of patients with obsessive-compulsive disorder (OCD) despite inconsistencies. Although several confounding factors have been investigated to explain the conflicting results, the findings remain mixed. This study aimed to investigate cognitive dysfunction in patients with OCD using a metaanalytic approach. Aim and Objectives: The present study aimed to assess the cognition in OCD and its relation with CRP, ESR levels Subjects and methods: This research was a casecontrol study one conducted on 120 subjects (60 OCD patients and 60 control subjects) cases were subjected to clinical diagnosis of OCD using Structured Clinical Interview according to DSM-5, and all subjects were submitted to Yale- Brown Obsessive-Compulsive Scale, Beck anxiety inventory, MoCA, ESR (Erythrocyte Sedimentation Rate) and, CRP blood sampling.Results:No statistical significance differences between cases and control group in demographic data or frequency of smoking. There was a statistical significance increase in frequency of impairment among urban resident and non-working cases. There was no statistical significance relation between Montreal Cognitive Assessment results and Yale Brown OCD Scale, Beck anxiety inventory but there was a statistical significant increase in frequency of sever beck depression inventory among the impaired cognitive cases. There was a statistical significance negative correlation between MOCA score and all ESR 1st, ESR 2nd, CRP, YBOCS and BDI. Conclusion: Patients with OCD appear to have cognitive deficits. Cognitive function in OCD patient was correlated with ESR,CRP, YBOCS and BDI scores. ESR CRP can be used in diagnosis of cognitive function in OCD