Idiopathic pulmonary fibrosis (IPF) is a chronic and usually fatal lung disease of unknown etiology. The aim of this study was to describe clinical and polysomnographic features of sleep-related breathing disorders (SRBD) and to identify predictors of obstructive sleep apnea (OSA) in IPF patients. Eight hundred fifty-seven patients with IPF were admitted to the Cleveland Clinic from 2001 to 2005. An all-night polysomnogram (PSG) was performed in 18 of them to investigate complaints suggestive of sleep-disordered breathing. OSA was confirmed in 11 of the 18 IPF patients with complaints suggestive of sleep apnea, while the remain 7 patients had a diagnosis of primary snoring or upper airway resistance syndrome (UARS). All patients showed a reduction in sleep efficiency, REM sleep, and slow wave sleep. The apnea-hypopnea index (AHI) was positively correlated with body mass index (p < 0.0001, r = 0.80). The REM AHI and overall AHI were negatively correlated with FEV(1) (p = 0.008, r = -0.59 and p = 0.04, r = -0.49, respectively) and FVC percentages (p = 0.03, r = -0.50 and p = 0.08, r = -0.42, respectively). Our study is the first describing SRBD in IPF patients. An increased BMI and a significant impairment in pulmonary function testing may be predictors of OSA in this population. In the absence of effective treatments for IPF, the diagnosis and treatment of comorbid SRBD may lead to improvements in quality of life.