Learning to manage stress is an important lifestyle change for participants in cardiac rehabilitation programs. Progressive muscle relaxation (PMR) is one stress management approach that has produced positive benefits among different patient populations. The purpose of this study was to identify the effects of learning and practicing PMR in a population of cardiac rehabilitation patients. Blood pressure and heart rate data, and scores on the Spielberger State-Trait Anxiety Inventory (STAI™) were collected from a treatment group and a control group of patients enrolled in phases II and III of cardiac rehabilitation. Analysis of the data revealed positive effects of PMR on the variables heart rate and state of anxiety. In addition, written evaluations of PMR from patients in the treatment group indicated a high degree of subjective satisfaction with PMR as a means to reduce stress in their lives.