Interoperability has become one of the big problems of e-commerce since it was born. A number of B2B standards like ebXML, UDDI, RosettaNet, xCBL, etc. emerged recently to solve the interoperability problem. UDDI and ebXML axe the leading standards in the area of e-commerce that provide different solutions for interoperability. UDDI standard provides a service based solution that proposes a registry standard for companies to publish their services on the web. On the other hand, ebXML provides a process based solution. It proposes several standard specifications like ebXML Messaging Service Specification (ebMSS) to achieve messaging interoperability, ebXML Business Process Specification (ebBPSS) and ebXML Collaboration Protocol Profile/Aggreement (ebCPP/A) to provide business process and partner profile interoperability, ebXML Registry Service Specification (ebRSS) and ebXML Registry Information Model (ebRIM) to describe a registry/repository that provides a classification mechanism to achieve partner discovery.