['Many patients undergoing bariatric surgery have severe comorbidities, including obstructive sleep apnea (OSA). We suspected that sleep apnea was underdiagnosed in our study population.', 'A retrospective chart review of our bariatric database was conducted comparing OSA evaluation based on clinical parameters (Era 1) with mandatory OSA evaluation for all patients (Era 2).', 'In both Era groups approximately 19% of patients presented to our program with an established diagnosis of OSA. In Era 1 this increased to 56% based on clinical parameters and in Era 2 this increased to 91% with mandatory polysomnography testing of all patients.'] Is potentially life-threatening sleep apnea unrecognized without aggressive evaluation?