Data warehouse modeling is a complicated task, which involves both knowledge of business processes and familiarity with operational information systems structure and behavior. Several modeling techniques were suggested to utilize the operational system structural or behavioral model in order to construct a data warehouse conceptual model. However, these techniques are hardly applicable for modeling largescale systems, as they require acquaintance with the business processes and ability to select relevant transactional entities. They require multiple manual actions because discovering measures and relevant dimensional entities are unassisted, and they usually disregard the process perspective. In this paper we propose a technique for data warehouse model construction based on the Object Process Methodology, and demonstrate it on a case study emphasizing its advantages over other techniques.