Patient compliance is paramount in the effectiveness of therapeutic regimens. Without compliance therapeutic goals cannot be achieved, resulting in poorer patient outcomes. The social and psychological factors thought to influence compliance are identified as (a) knowledge and understanding including communication, (b) quality of the interaction including the patient-provider relationship and patient satisfaction, (c) social isolation and social support including the effect of the family, (d) health beliefs and attitudes-health belief model variables, and (e) factors associated with the illness and the treatment including the duration and the complexity of the regimen. Noncompliance is a significant problem and a major challenge for the health care team. Practical advice is offered for nurses and other health care professionals to increase patient compliance with therapeutic regimens. These include factors involved in the patient-provider relationship, communication skills and information-giving, and the mobilization of existing social support networks. Further research is needed to provide more conclusive results into the factors involved in patient compliance and to test the effectiveness of compliance-enhancing strategies.