An automated accountability system for special nuclear materials (SNM) is under development at Argonne National Laboratory-West. Phase I of the development effort has established the following basic features of the system: a unique file organization allows rapid updating or retrieval of the status of various SNM, based on batch numbers, storage location, serial number, or other attributes. Access to the program is controlled by an interactive user interface that can be easily understood by operators who have had no prior background in electronic data processing. Extensive use of structured programming techniques make the software package easy to understand and to modify for specific applications. All routines are written in FORTRAN.