Patient navigation programs are emerging that aim to address disparities in clinical trial participation among medically underserved populations, including racial/ethnic minorities. However, there is a lack of consensus on the role of patient navigators within the clinical trial process as well as outcome measures to evaluate program effectiveness. A review of the literature was conducted of PubMed, Medline, CINHAL, and other sources to identify qualitative and quantitative studies on patient navigation in clinical trials. The search yielded 212 studies, of which only 12 were eligible for this review. The eligible studies reported on the development of programs for patient navigation in cancer clinical trials, including training and implementation among African Americans, American Indians, and Native Hawaiians. A low rate of clinical trial refusal (range, 4%-6%) was reported among patients enrolled in patient navigation programs. However, few studies reported on the efficacy of patient navigation in increasing clinical treatment trial enrollment. Outcome measures are proposed to assist in developing and evaluating the efficacy and/or effectiveness of patient navigation programs that aim to increase participation in cancer clinical trials. Future research is needed to evaluate the efficacy of patient navigators in addressing barriers to clinical trial participation and increasing enrollment among medically underserved cancer patients.