Whereas computer technology allows for the automation of experimentation and data collection, the process of stimulus production has remained a relatively labor-intensive process. A program for automatic computer generation of novel nonverbal stimuli is described in this paper. The program, STIMGEN, allows menu-driven control over the type and appearance of stimuli. Data are presented in which two monkeys matched to sample with high accuracy using stimuli generated with STIMGEN. These data are interpreted to support the usefulness and value of automatic stimulus generation in a variety of applications.