Recruitment of research participants often has not obtained a desired sample size, thereby becoming a major problem inhibiting investigators' ability to adequately test the specified hypotheses. Social marketing with its four Ps, originally developed by the business world to sell products and adapted for public health initiatives, is proposed as a dynamic comprehensive conceptual framework to apply marketing principles and practices to enhance participant recruitment. Applying a social marketing approach to research recruitment would require initial investigation to understand the motivations of the target audience in regard to research participation, and continued research throughout the main project to adapt the recruitment efforts as limitations arise. Additional funding would be needed for successful social marketing research recruitment programs to be systematically implemented and evaluated as part of research projects. In this paper, we define social marketing concepts, briefly review the available literature supporting social marketing applied to recruitment for research studies, and consider ethical issues that may arise when using a social marketing approach.