This study sought to determine which combination of criteria would accurately predict the success of students in graduate education who began their graduate studies on probationary admission status. Variables examined included grade point average (GPA) after 9 hours of graduate coursework, Graduate Record Examination (GRE) verbal, quantitative, and verbal scores, and final graduate GPA. The study examined the degree completion rates of 388 Master's degree students granted probationary admission and 1,135 Master's degree students granted regular admission between 1988 and 1994 at a medium-sized Midwestern university for whom GRE scores were available. It found that for probationary students, the best predictors of success (degree completion) were GRE quantitative scores, GRE analytical scores, and the nine-hour GPA. Overall, only the GRE verbal scores and the nine-hour GPA emerged as predictors of success for regular admission students. Since results varied on both sets of data when area analyses were performed, it appeared that predictors of success were dependent on major area of study. Three appendixes provide 27 tables comparing the success of probationary and regular admission students overall and by discipline. (Contains 16 references.) (MDM)