Pediatric-onset obsessive-compulsive disorder (OCD) is underdiagnosed, and many affected children are untreated. The present study seeks to evaluate the presence and the clinical impact of OCD and obsessive-compulsive symptoms (OCS) in a large sample of school-age children. In Phase I, we performed an initial screening using the Family History Screen (FHS). In Phase II, we identified an ‘at-risk’ sample, as well as a randomly selected group of children. A total of 2,512 children (6-12 years old) were assessed using the FHS, the Development and Well-Being Assessment (DAWBA), the Strengths and Difficulties Questionnaire (SDQ), and the Child Behavior Checklist (CBCL). Data analyses included descriptive and multivariate analytical techniques. 2,512 children (mean age: 8.86 +/- 1.84 years; 55.0% male) were categorized into one of the three diagnostic groups: OCD (n = 77), OCS (n = 488), and unaffected controls (n = 1,947). There were no significant socio-demographic differences (age, gender, socioeconomic status) across groups. The OCS group resembled the OCD on overall impairment, including school problems and delinquent behaviors. However, the OCD group did have significantly higher rates of several comorbid psychiatric disorders, including separation anxiety, generalized anxiety, and major depressive disorder, than OCS or unaffected controls. Moreover, the OCD group also scored higher than the SDQ, as well as on each of CBCL items rated by the parent. Our findings suggest that there is a psychopathological continuum between OCS and OCD in school-aged children. The presence of OCS is associated with functional impairment, which needs further investigation in longitudinal studies.