Bariatric surgery is a valid treatment alternative for obese patients with obstructive sleep apnea (OSA), but subjects who are overweight or obese represent a poor model to investigate the role of OSA treatment on cardiovascular variables, calling into question the attribution of cardiovascular and metabolic problems associated with OSA with excess weight. Seventeen patients with significant obesity who demonstrated OSA with a high apnea-hypopnea index (AHI) were treated with bariatric surgery alone after refusal of nasal continuous positive airway pressure (CPAP) treatment. At approximately 3 years post-surgery, subjects demonstrated a significant drop in blood pressure measured at rest, improvement in sleepiness and fatigue visual analogue scales, but continued to complain of daytime sleepiness. Polysomnography in these subjects demonstrated relative improvement in AHI, but patients continued to have a significant number of respiratory events and episodes of flow limitation.  Subsequent treatment with a dental device led to further improvement in nocturnal respiration, but did not reduce AHI to a normal range on repeat polysomnography. In this study we demonstrate that bariatric surgery alone and in conjunction with a dental device may significantly reduce AHI but does not eliminate daytime fatigue and sleepiness. Systematic long term follow-up examining the persistence of sleep related abnormalities should be performed particularly if daytime fatigue or sleepiness is still present in patients with OSA after treatment with bariatric surgery alone.