The Stanford Medical Youth Science Program (SMYSP) is a biomedical pipeline program that seeks to diversify the health professions by providing academic enrichment in the medical sciences and college admissions support to very low-income high school students. Each summer 24 students are recruited from over 250 California high schools for the five-week residential program, led by 10 undergraduate students. Participants divide their time between classroom instruction, anatomy practicums, hospital field placements, research projects, and college admissions advising. Since its inception in 1988, 405 students have completed SMYSP and 96% have been observed for up to 18 years. The majority are from underrepresented minority groups (33.3% Latino, 21.7% African American, 4.0% Native American), many with poor academic preparation. One hundred percent of age-eligible participants have graduated from high school, and 99% have been admitted to college. Of those admitted to college (and not currently college students), 81% have earned a four-year college degree, the majority majoring in biological and physical sciences (57.1%). Among four-year college graduates, 52% are attending or have graduated from medical or graduate school. Many of the four-year college graduates (44.4%) are becoming or have become health professionals. This program, distinguished by direct participation in the sciences, strong mentoring, college admissions preparation, and long-term career guidance, has been highly successful in reaching low-income students and preparing them for medical and other careers. Results highlight the need to track students for as long as 10 to 15 years to accurately assess college graduation rates and acceptance to medical and graduate school.