This work addresses the need within hospitals for integration of segregated decision supports systems (DSS). A DSS is a computer-based application that helps users analyze business and clinical data for decision-making. Separate DSSs store data in segregated repositories resulting in duplicated data storage, manual retrieval of information, likelihood of data manipulation errors, and software support tool incompatibilities that increase the cost of data retrieval. Data collection, extraction and analysis problems encountered by pharmacists' in using segregated data repositories illustrate the need for integration. A model for an integrated data repository or data warehouse solution is presented. Before the implementation of a data warehouse it is important to take into account a number of planning and design considerations. Examples of hospital data warehouse implementations are presented.