Few studies have been conducted on nontraditional student attrition in postsecondary vocational educational programs. This lack of attention is due to methodological limitations, lack of priority on data collection in vocational education, and lack of perceived need for research. The conceptual model of student attrition in postsecondary vocational education proposed in this paper is is adapted from other conceptual and theoretical approaches found in studies conducted in two- and four-year postsecondary institutions. The model draws also upon the previous research on traditional students, including Spady's model of the undergraduate dropout process (1971), Tinto's longitudinal model of student persistence (1975), and Pascarella et al.'s model (1983). Other sources include studies that focus on nontraditional students, such as Bean and Metzner's model of nontraditional student attrition in postsecondary education settings and Brown and Kayser's model of educational adjustment. The proposed model includes several new variables. It is developed to account for attrition among different subgroups of nontraditional students. Exogenous factors describing students' backgrounds include disability and outside community agency support received. The model also seeks to examine the interrelationships of disability and disadvantage with external environmental factors. Several concepts described and tested in other models, "institutional commitment" and "social integration," are expanded in this model. (157 references) (YLB)