Jail administrators have been hard-pressed to meet higher demands for accurate recordkeeping management caused by increases in jail populations and State and national reporting requirements. Small-sized to medium-sized jails need a central source of timely, reliable information but are stymied by limited personnel and financial resources. LOCKUP was designed to improve jails' ability to collect, maintain, and disseminate accurate, timely information for internal operations and external reporting demands. LOCKUP is also affordable for jails lacking the resources of larger facilities. LOCKUP was successfully beta tested at two sites, with populations ranging from 35 to 342 inmates. The test demonstrated that LOCKUP met the basic recordkeeping needs of both sites. System administrators at the beta test sites reported LOCKUP was easy to maintain and customize to their needs. Regional seminars would be the best way to familiarize jail administrators with LOCKUP. A methodological description is appended. (Author abstract modified)