Introduction: Patients with obsessive-compulsive disorder (OCD) have historically been considered at low risk for suicide, but recent studies are controversial. Objective: To study the prevalence of suicidal thoughts and attempts in OCD patients and to compare those with and without suicidality according to demographic and clinical variables. Methods: Fifty outpatients with primary OCD (Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition) from a Brazilian public university were evaluated. The Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) was used to assess OCD severity, the Beck Depression Inventory to evaluate depressive symptoms and the Alcohol Use Disorders Identification Test to assess alcohol problems. Results: All patients had obsessions and compulsions, 64% a chronic fluctuating course and 62% a minimum Y-BOCS score of 16. Half of the patients presented relevant depressive symptoms, but only three had a history of alcohol problems. Seventy percent reported having already thought that life was not worth living, 56% had wished to be dead, 46% had suicidal ideation, 20% had made suicidal plans, and 10% had already attempted suicide. Current suicidal ideation occurred in 14% of the sample and was significantly associated with a Y-BOCS score ≥16. Previous suicidal thoughts were associated with a Beck Depression Inventory score ≥19. Conclusion: Suicidally has been underestimated in OCD and should be investigated in every patient, so that appropriate preventive measures can be taken.