This study was conducted to investigate the current status and problems of interlibrary loan involving the libraries in Taiwan, Republic of China. A questionnaire was administered to 212 libraries of the Library Consortium on Humanities & Social Services and the Science & Technology Library & Informatron Network. The results indicated that: 1. The average fill rate of interlibrary loan requests is above 80%. 2. The average turnaround time of interlibrary loan requests is about 10-20 days. 3. The factors affecting the fill rate and time effectiveness are: ① lack of verification tools and union lists; ② inaccuracies of citations on interlibrary loan request forms. 4. The libraries with large collections are the principal lenders, and they lend much more than they borrow.