This study investigated the use of rapid prototyping methodologies in two projects conducted in a natural work setting. It sought to determine the nature of its use by designers and customers and the extent to which its use enhances traditional instructional design (ID). With respect to describing rapid prototyping use, the results pertain to designer tasks performed, the concurrent processing of those tasks, and customer involvement. With respect to describing the enhancements facilitated by rapid prototyping, the results pertain to design and development cycle-time reduction, product quality, and customer and designer satisfaction. In general, the two projects studied show ID efforts that created products that were usable for a conveniently long period of time without revision; delivered in a shorter period of time than would have been expected using traditional techniques; and received by satisfied customers who had been involved throughout their development. In other words, the rapid prototyping methods lived up to their promised benefits.