To date, there have been many reports on the use of decision support systems (DSS) and knowledgebased systems (KBS) in organizations. Little of this research evaluates the impact of commercial systems on the performance of the organization using the system. This study attempts to shed some light on this intellectual domain. This paper reports on a field-based investigation into the effects of the use of MUDMAN™ (a commercial expert systems product) on the information-processing capacity of N.L. Baroid, an oil services firm. The study uses the notions of organizational programs as defined by March and Simon and operationalizes the information processing capacity framework £ut forth by Galbraith to show how information-processing capacity was affected when the MUDMAN system was used at Baroid.