A description is given of DISC (discrete-event simulation in C), which provides an environment for creating and executing discrete-event simulation models in which the event routines are coded in C. It is designed to be similar to FORTRAN-based simulation languages such as GASP, SLAM and SIMAN. In DISC, the C functions required to support discrete-event simulation are organized into library modules. Since DISC is written entirely in C the user can make use of sophisticated data structures and define his/her own data types using structures. DISC is portable across hardware and operating systems. Preliminary experience indicates significant reductions in both execution time and memory requirements when compared with SLAM and SIMAN versions of the same models.