In recent years, Software-as-a-Service (SaaS) is gaining momentum with more and more successful adoptions. Several companies including some well known names have embraced this new model for software distribution. In this paper we present ODBIS, an open source infrastructure to build and deliver On-Demand Business Intelligence Services. The ODBIS platform constitutes a future perspective to provide SaaS deployment model for business intelligence applications. ODBIS offers a unified and innovative multi-layered architecture to support different business intelligence needs, this includes: (i) Core business intelligence services which cover essential data warehousing tasks as meta-data management, data integration, reporting and analysis; all built in an integrated manner using standard APIs. (ii) Services for data warehousing projects management and models design based on a model-driven approach using the 2 Track Unified Process (2TUP) and the Model Driven Architecture (MDA) standard...