International Journal of Information Studies Yasser Oussalah, Nadia Zeghib 4 3 2012 The composition of heterogeneous Web services is a key aspect of usability and applicability of Web services in different application domains such as business applications, healthcare, and e-government. Unfortunately, the reuse of Web services raises composition issues since they present, most of the time, mismatching at different levels such as structural, behavioral and non-functional. The resulted mismatches require adaptation to insure the correct working between Web services. This paper presents an effective adaptive Web service composition. It gives especially a formal specification of operations which enable to compose and adapt services at runtime. This specification is given in Maude language as a logical framework. Thanks to many Maude tools, formal analysis may be easily performed