The goal of this study was to develop a means for better assessing the potential success of a regional interlibrary loan program. Descriptive information and qualitative data on funding, policies, and procedures were gathered for five regional interlibrary loan programs in New York State from three sources-- questionnaires sent to each member library, on-site visits, and a weighted sample of loan requests. A profile of population, socio-economic characteristics, and available library resources was created for each region. Quantitative data were analyzed by rank order correlation or a confidence test of significant similarities and differences. Conclusions were made concerning the impact on interlibrary loan effectiveness of three factors: (1) regional characteristics; (2) the extent and nature of regional interlibrary loan; and (3) loan processing and funding. Fourteen general recommendations were made for funding and loan processing, specific suggestions and proposals were outlined for each regional interlibrary program, and a data collection method was suggested for future performance measurement. The appendices include the regional profile. (KP)