Because Obstructive Sleep Apnea Syndrome (OSAS) patients may be treated for comorbidities prior to OSAS diagnosis, we examined the health care utilization records of 181 OSAS patients and those of matched controls. We compared OSA patient health care utilization for a ten-year interval prior to diagnosis to those of randomized age-, gender-, and geographically-matched controls from the general population. We found that OSAS patients used approximately twice the resources (as defined by physician claims and stays in hospital) in the ten years prior to their diagnosis. Physician claims for cases totaled $686,365 ($3,972 per patient) compared to $356,376 ($1,969 per patient) for the controls for the length of the study. Utilization was significantly higher in 7 of 10 years prior to diagnosis. OSAS patients also had more hospitalizations: they had 1,118 nights (6.2 per patient) in hospital versus 676 nights (3.7 per patient) for controls over the ten-year period. Thus OSA patients are heavy users of health care resources ten years prior to diagnosis.