Numerous policy initiatives have highlighted the need for the United States to produce more STEM graduates to meet labor market demands. This study challenges that narrative by focusing on the many STEM bachelor's degree holders who do not currently go on to work in a STEM field. Data from the Educational Longitudinal Survey of 2002 (ELS:2002) shows that over 25 percent of STEM baccalaureate graduates did not intend to remain in a STEM field by age 30. Through a series of logistic regression models and the application of human capital theory and social cognitive career theory (SCCT), we explore the demographic, postsecondary, and labor market variables that may influence a student's decision to remain in a STEM career. Results suggest that non-Asian minority students are significantly more likely to leave the STEM professional domain either shortly after obtaining a bachelor's degree or by age 30. Certain experiences (namely faculty research and fieldwork) were associated with a greater likelihood of STEM career entry/persistence, and transfer students also appeared at risk of early departure from STEM career fields. Students who lacked social connections or were unable to relocate for work also reported a perceived lack of job openings in STEM at significantly higher levels.