Background: Obstructive sleep apnea (OSA) is widely prevalent, but under-diagnosed. It is not screened for widely. Physicians tend to only screen those they consider at risk. This determination is made either by assessment of body habitus or significant symptoms. Methods: Patients without known OSA at a cardiology clinic were screened using a questionnaire for signs and symptoms of OSA. Patients with high scores were referred for testing. Results: The patient group included 102 patients who obtained OSA testing. Obstructive sleep apnea was highly prevalent in the patients who screened positive, with 84% of patients referred for testing positive for OSA. As OSA became more severe, patients had more comorbidities. Body mass index did not correlate with presence of OSA or severity of OSA. Conclusions: Obstructive sleep apnea is highly prevalent in at risk populations, such as those found in cardiology clinics. Obstructive sleep apnea does not correlate with body habitus, so physician initiated screening for patients with large BMI is not adequate. Wide screening in at risk populations should be employed.