Annually, over 350,000 persons require cardiopulmonary resuscitation (CPR), either in or outside of the hospital. With obesity a rising health issue in the United States, concerns exist regarding the efficacy of quality compressions for CPR in obese patients. The aims of this study were to determine if the compressions for three adult simulation manikins (normal, obese, and morbidly obese) met quality guidelines; to examine any differences in quality of chest compressions performed by health care providers between the three manikins; and to examine the effect of participant characteristics on the quality of chest compressions in obese and morbidly obese manikins. A randomized controlled design was used. Sixty-one health care providers performed chest compressions on the three simulation manikins. Results showed that performance on the normal-sized manikin was significantly better than that on both obese and morbidly obese manikins. Participant characteristics were significantly associated with quality of chest compressions. The effectiveness of compressions in obese and morbidly obese CPR recipients has yet to be determined.