The purpose of this exploratory, phenomenological study was to understand developmental mathematics in community college by examining the beliefs and worldviews of developmental mathematics instructors. This study interviewed 11 instructors in 4 demographically different community colleges within a single state with decentralized developmental mathematics programs in order to understand instructors' perceptions of the mission and outcomes of developmental mathematics, and suggestions for improving outcomes in developmental mathematics. This study also examined how instructors differentiated teaching developmental and college-level mathematics. Central to this study was an examination of instructors' personal theories of practice, which included instructors' epistemological worldviews. Although not all instructors differentiated teaching developmental and college-level mathematics, this study revealed that many instructors perceived developmental differences in student metacognitive skills and affective behaviors. Colleges whose faculties perceived a difference in developmental and college-level mathematics were in agreement as to how to improve outcomes in developmental mathematics. Instructors in this study understood the goal of developmental mathematics in pragmatic terms: helping students progress into the college-level mathematics required by their degree or certificate program. However, the metrics used by instructors to assess the success of developmental mathematics were neither uniform nor linked to the program goal. Instructors reported problems related to student learning, lack of progress, placement, instruction, and instructor preparation, and suggestions for improving outcomes that were college-specific and called for college- or system-level action. Examining instructors' worldviews using vignettes revealed that (1) instructors did not identify with one particular worldview, and (2) instructors intentionally held multiple worldviews. This study examined the applicability of Schraw and Olafson's (2002) worldview typology with instructors in higher education, and raised the possibility of a student support worldview. Developmental instructors in community colleges practice within their own understandings of developmental mathematics, without the guidance of a formal theory or philosophy. This study contributed to the theory that self-regulation is a key distinguishing characteristic between developmental and college-level students in community colleges, and supports the notion that the role of the developmental mathematics instruction is the promotion of self-regulation (Ley & Young, 1998; Wambach & Brothern, 2000). [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/en-US/products/dissertations/individuals.shtml.]