This paper presents an experimental evaluation of the latency performance of several implementations of Simple Object Access Protocol (SOAP) operating over HTTP, and compares these results with the performance Of JavaRMI, CORBA, HTTP, and with the TCP setup time. SOAP is an XML based protocol that supports RPC and message semantics. While SOAP has been designed as an interoperable business-to-business protocol usable over the Internet, we believe that applications will also use SOAP for interactive web applications running within an intranet. The objective of this paper is to identify the sources of inefficiency in the current implementations of SOAP and discuss changes that can improve their performance. SOAP implementations studied include Microsoft SOAP Toolkit, the SOAP: Lite Perl module, and Apache SOAP.