In the current globalized world, characterized by strong Web based interactions, relationships between people and organizations are subject to fast changes. This situation justifies the need for an approach that can capture business changes and quickly implement them into computational systems. Considering that some business logic portions are quite volatile and susceptible to changes and other portions are quite stable and less susceptible to changes, a model for flexible service integration using business rules and service ontology is proposed. The volatile portions are externalized as business rules and the stable portions as Web services. This paper presents the main concepts of the model and an overview of the proof of concept applied to validate the model. ©2008 IEEE. Dhillon, G., Hackney, R., IS/IT and dynamic business change (2000) Proceedings of the 33rd Annual Hawaii International Conference on System Sciences, , Maui, Hawaii(2007) Blaze Advisor, , http://www.fairisaac.com/Fairisaac, Fair Isaac Corp(2007) Jrules, , http://www.ilog.com/products/jrules, ILOG, IncFriedman-Hill, E., (2003) Jess in Action, , Manning Publication CoHe, H.. What is Service-Oriented Architecture?, O'Reilly, WebServices.XML.com, 2003W3C. Web Services Architecture, Working Group Note 11, 2004Mahmoud, Q., Service-Oriented Architecture (SOA) and Web Services: The Road to Enterprise Application Integration (EAI) (2005) SDN - Sun Developer NetworkOASIS. Web Services Business Process Execution Language Version 2.0. May/2006Nagl, C., ViDRE - A Distributed Service-Oriented Business Rule Engine based on RuleML (2006) Proceedings of the 10th IEEE International Enterprise Distributed Object Computing Conference (EDOC'06)Kamada, A. and Mendes, M. Business Rule Engine Applied to eGovernment Services Integration, I3E / IFIP 2005, Poznan, Poland, 2005SBVR - Semantics of Business Vocabulary and Business Rules (2006) Adopted Specification, , OMGHildreth, S., Rounding Up Business Rules (2005) ComputerWorld Software. IDG(2004) Initial Submission to BSBR - Business Semantics of Business Rules, , IBMBSBR - Business Semantics of Business Rules RFP, , OMGMDA Guide Version 1.0.1 (2003), OMGWeb Service Execution Environment (WSMX) (2005) Member Submission, W3C. , WSMX, 3WSMO, Web Service Modeling Ontology (WSMO), W3C Member Submission 3, 2005Charfi, A., Mezini, M., Hybrid Web Service Composition: Business Processes Meet Business Rules (2004) ICSOC 2004 - International Conference on Service Oriented Computing, , New York City, USAElrad, T., (2004) Introduction to Aspect-Oriented Software Development, , Addison Wesley ProfessionalOrriens, B., Yang, J., (2006) Specification and Management of Policies in Service Oriented Business Collaboration, , Tilburg University, Macquarie University, AustraliaBoley, H., Tabet, S., RuleML (2007) The Rule Markup Initiative, , http://www.ruleml.orgKamada, A., Service Execution based on Business Rules (2006), PhD Thesis in Computing Engineering, Unicamp, Campinas, BrazilUnlock data and functions in your legacy systems (2006) CrossVision, , Software AGhttp://www.egoia info, , eGOIA, Electronic Government Innovation and AccessProduction Rule Representation Request For Proposal OMG (2003) Document: Br/2003-09-03, , OMGW3C. SWRL: A Semantic Web Rule Language Combining OWL and RuleML. W3C Member Submission, 2004Levenick, J., Simply Java: An Introduction to Java Programming (2005) Programming Series, , Charles River Media, First edition