The differential features of childhood-onset obsessive compulsive disorder (OCD) compared to adult-onset OCD are being more of a focus of attention in recent years. The aim of this study was to determine the clinical and neuropsychological profiles of children and adolescents diagnosed with childhood-onset OCD and to investigate the association between the duration, severity, comorbidity, and family history of the disorder and clinical and neuropsychological functional impairments. Thirty-five OCD patients (patient group) and 35 healthy control subjects (control group) between 8-15 years of age were included. To investigate the neuropsychological profiles, the Wisconsin Card Sorting Test (WCST), Stroop Test, and Continuous Performance Test (CPT) were applied. To assess the clinical and behavioral profiles, the Children's Depression Inventory (CDI), Conner's Parent Rating Scale (CPRS-48), and the Yale Brown Obsessive Compulsive Scale (YB-OCS) and Yale Global Tic Severity Rating Scale (YGTSRS) were given. Based on the performance in the WCST, Stroop Test, and SPT, the results of the study reveal that childhood-onset OCD patients have statistically significant worse performance compared to healthy controls in terms of executive functions, sustained attention, and motor inhibition tasks. Excluding the comorbid diagnoses, childhood-onset OCD patients did not show a difference in behavioral problems, but they had higher levels of anxiety compared to healthy controls. The findings of this study reveal that independent of the duration, severity, comorbid problems, and anxiety levels, the disorder itself is associated with worse performance in executive functions, attention, and motor inhibition processes, and a positive family history of OCD is an important risk factor. Long-term follow-up studies with patients diagnosed with childhood-onset OCD would be a logical next step in order to determine the cause-effect relation between the disorder and cognitive impairments.