This qualitative transcendental phenomenological study addressed the perceptions of at-risk, Generation Z, undergraduate Science, Technology, Engineering and Mathematics (STEM) graduates at a Historically Black College and University (HBCU), related to their persistence and retention. The problem was that many at-risk, Generation Z undergraduate STEM HBCU students are academically underprepared for higher education, and many fail to complete their degree, resulting in low student retention and graduation rates. If the United States is expected to maintain competitiveness within international industry, which is predominantly motivated by STEM, institutional educational systems must develop and implement methods to successfully reassure and support all student populations. This study investigated how at-risk, Generation Z undergraduate Science, Technology, Engineering and Mathematics (STEM) graduates, currently working in their field or pursuing higher degrees, experienced academic success at their HBCU. The theoretical framework of this study consists of Astin's Theory of Involvement, Tinto's Model of Institutional Departure, and Deci and Ryan's Self-determination Theory, whereas, they agreed that the more persistent and involved students became within their institution, socially and academically, the more satisfied students became, and therefore, were retained through graduation. Data collection consisted of a demographic questionnaire, semi-structured interviews, and member checking of interview transcriptions of six graduate participants. The research questions were based on the perceptions of the underlying impressions of pre-enrollment, personal persistence, and institutional retention, as they relate to STEM graduates. The study participants were recent Bachelor of Science computer science degree recipients of one of six specialties: digital gaming, game development, computer information systems, mathematics, computer information security, and network engineering. This research highlighted the importance of professor-student guidance, developmental programs, and student-student guidance working in unison to establish success in student persistence and retention in STEM undergraduate degree programs. The phenomenological methodology of this study stimulated and reinforced present and future STEM students, families, educational institutions, and other STEM stakeholders. Recommendations for future research is to seek out participants also graduating from STEM programs with the added academic difficulties of a mathematics specialty or an engineering program, whereas, not only will the participant, as in this study, have the combinations of computer languages and programming, they will also have coursework in higher level mathematics and advanced statistics. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]