Middleware eases the development of distributed applications. Expansion in the enterprise world entails integration of heterogeneous products, and there is a demand for a balance between performance, interoperability and security in the distributed applications. Windows Communication Foundation (WCF) offers a technology to build service-oriented, secure, reliable and interoperable distributed applications. The current literature contains few studies comparing the performance of WCF with other technologies, but it does not address the performance of WCF in a cross-technology communication. This master thesis experimentally evaluates the performance of WCF in unsecure and secure variants. It evaluates the performance in on-machine and cross-machine communication, and it addresses the performance of WCF’s interoperability with ASMX and Java. We have developed the service and client applications in both secure and unsecure variants. The experiments are then conducted using these applications in a laboratory setting. We have measured the performance in terms of throughput, response time, processor and memory utilization during the experiments. Our results show that in unsecure variants, the WCF service in cross-machine communication has the best response time than on-machine communication on small datasets. However, on large datasets the service in on-machine communication has the best response time. In secure variants, the service in on-machine communication has better response time than the cross-machine communication. In both secure and unsecure variants, the service has better throughput and consumed lesser resources in cross-machine communication than in on-machine communication. In case of WCF’s interoperability with ASMX and Java, both the secure as well as unsecure WCF service show more scalable performance for the WCF client than for ASMX and Java clients. The secure as well as unsecure service show better performance for the ASMX client than for the Java client. The unsecure variants of WCF service perform better than the secure variants, except in a few cases of memory utilization. Therefore, the performance of the WCF service degrades due to security.