Since the 1970s, globalization, changes in technology, and the weakening of unions have transformed employment relations in the United States. One indication of this transformation is the rise in precarious employment, or “employment that is uncertain, unpredictable, and risky from the point of view of the worker” (Kalleberg, 2009, p. 2). Existing research indicates that young people between the ages of 16 and 24 are more likely than workers from other age groups to be in precarious work. There is also a growing body of literature on the relationship between employment and short- and long-term health outcomes, including psychological distress and depression. However, much remains unknown about the pathways and mechanisms linking employment trajectories with health outcomes for young adults, which will be critical for designing effective program and policy interventions. This dissertation used data from the National Longitudinal Study of Adolescent to Adult Health to create a multi-dimensional measure of precarious employment, and to assess the relationship between changes in precarious employment and changes in self-rated general health, mental health, and behavioral health. First, it used latent class analysis to identify precarious employment groups at Wave III and Wave IV, and assessed the factors associated with precarious employment at that time. From there, the precarious employment groups from Wave III and Wave IV were linked, in order to create a variable representing change in precarious employment over time, and factors associated with the change in precarious employment were assessed. In addition, this study assessed whether participation in job-training made a difference, in terms of the change in precarious employment over time. Lastly, generalized linear models were used to assess the relationship between changes in precarious employment and changes in health. Findings indicated that age, gender, race/ethnicity, and education significantly associated with precarious employment at Wave III, and with the change in precarious employment from Wave III to Wave IV. There was not a significant relationship between participation in job-training and changes in precarious employment. Lastly, changes in precarious employment were not associated with changes in health. It is argued that these findings have important implications for policy and practice; however, more research is needed, in order to better understand emerging adults’ experiences in precarious employment today.