Researchers are far from understanding the mechanism(s) of action of hormone replacement therapy (HRT) on the cardiovascular system. Moreover, the results of clinical trials that can clarify these dilemmas will not be available for several years. As clients seek guidance in making the pivotal decision about taking HRT, it is important that practitioners understand what the current research reveals about its risks and benefits. This article addresses the role of HRT in primary and secondary prevention and includes observational research, clinical trials (completed and in progress), benefits and risks, and implications for clinical practice in counseling patients.