In this paper, we address the issue of noncompliance with medical regimens in adult stem cell transplant patients. We review the definition, prevalence, and consequences of noncompliance and address whether or not we should alter our medical decision-making with regard to stem cell transplantation based on patient noncompliance. We discuss how the health care team should handle noncompliance issues and propose clinical guidelines for stem cell transplant programs to consider regarding evaluation and management of medical compliance.