A study was conducted in an attempt to provide comprehensive data about the characteristics of students enrolled in resident proprietary schools in Illinois. Students were administered a survey instrument modeled after the Student Profile Section of the American College Testing Program's assessment form and their Career Planning Profile Booklet. The instrument was given to 1,432 students in 35 proprietary schools, which included business, self-improvement, vocational schools, barber and cosmetology schools, and truck-driving schools. Student characteristics were obtained and analyzed in five general areas: Demographic and family background, high school background, experiences after high school and reasons for choosing the present school, experiences in the present school, and future expectations and job attitudes. Detailed findings and comparisons of proprietary school students to other students (in public high schools and community colleges) are reported in each area. Conclusions are detailed and include the following: Characteristics of students enrolled in proprietary schools vary markedly among the types of schools. Proprietary schools are seen as avenues to new or improved employment opportunities. Proprietary school students are less likely to come from middle-class families than collegiate students. Students have a generally high level of satisfaction with the quality of their instruction. (TA)