SUMMARY. The INNOVACQ and Geac Acquisitions Systems have been successfully implemented in several large academic libraries. All basic requirements for a full-scale acquisitions system have been met by both systems. Size, as measured by number of orders placed or number of subscriptions maintained, magnifies the problems, deficiencies, and difficulties of any system. This paper focuses on significant differences between the two systems, particularly as they relate to large academic libraries. These areas include capacity, in-house control and environmental concerns, backup procedures and printing, command structure, record structure, integration versus interfacing, password security, serials control, invoicing and fund accounting, and management reports.