In this qualitative systematic review, we evaluate studies of the demographic, innate, and environmental risk factors and correlates associated with the development of Obsessive-Compulsive Disorder (OCD) in epidemiological samples. We found that a significant proportion of the studies indicate that late adolescence is a period of increased vulnerability for the development of OCD; that OCD affects predominantly female adults and male children and adolescents; that those who are unmarried or abusing drugs are more likely to present with OCD; that OCD is a familial and genetic disorder, particularly when one considers symptom dimensions instead of categorical diagnosis and when the disorder begins at an early age; and that individuals with OCD from the community, like those seen in clinical settings, may be especially prone to present psychiatric conditions such as mood and anxiety disorders. Although there are plenty of data on the correlates and risk factors of OCD in epidemiological samples, more research is needed on other potential risk factors, including obstetrical and pregnancy problems, pre-morbid neurocognitive functioning, and streptococcal infections, among others.