Guided by well-established theories on student retention, a survey was developed and implemented to collect data about the college experience of STEM students at a four-year research university. Analysis of the survey data confirms ten constructs that captured different aspects of students' academic and social experiences. Among them, academic quality provided by the institution, students' formal academic integration, and motivation for active learning are identified to be the most influential factors to their retention. Different from students in non-STEM majors, financial pressure to fund college education and accessibility to faculty members outside the classroom are not significantly associated with STEM students' intention to depart. The findings also challenge the sociological emphasis on social engagement as the pivotal point for student retention in STEM majors. To improve student persistence in STEM majors, it is suggested the institutional administrators invest in improving faculty members' teaching skills, reducing class sizes, and engaging students in active learning and research projects.