This study examined the influence of mathematics course-taking on Latina/o science, technology, engineering, and mathematics (STEM) major persistence utilizing data from first-year STEM majors at a Hispanic-Serving Institution (HSI). Findings indicated that students who passed a first-term college-level mathematics course had significantly greater odds of persisting in STEM majors than those who did not, demonstrating the importance of early mathematics support to increased STEM major persistence.