Background data on State supreme court judges serving in 1980-81 covered birth place, type of education, prior governmental experience, type and length of law practice, and political party and religious affiliation. Data sources were biographical directories and questionnaires mailed to political science professors, judges, and court administrators in each State. Of the 180 questionnaires sent, approximately 75 percent were returned. The findings confirm previous studies which show that various selection systems produce judges with similar judicial credentials. Differences among judges in type of education, localism, type of law practice, and previous experience are due mainly to region rather than selection system. This study indicates, however, that merit selection systems, compared to other selection systems, tend to produce higher proportions of Protestant judges. Past research reports that Catholic and Jewish judges are somewhat more liberal than Protestant judges on certain social and economic issues; therefore, merit selection may have the indirect effect of producing conservative judicial policy. Future research should explore this possibility. 3 tables and 20 footnotes.