Each day new computers around the world connects to the Internet or some network. The increasing number of people and computers on the Internet has lead to a demand for more services in different domains that can be accessed from many locations in the network. When the computers communicate they use different kinds of protocols to be able to deliver a service. One of these protocol families are remote procedure calls between computers. Remote procedure calls has been around for quite some time but it is with the Internet that its usage has increased a lot and especially in its object oriented form which comes from the fact that object oriented programming has become a popular choice amongst programmers. When a programmer has to choose a distributed object middleware there is a lot to take into consideration and one of those things is performance. This master thesis aims to give a performance comparison between different distributed object middleware technologies and give an overview of the performance difference between them and make it easier for a programmer to choose one of the technologies when performance is an important factor. In this thesis we have evaluated the performance of CORBA, DCOM, RMI, RMI-IIOP, Remoting-TCP and Remoting-HTTP. The results we have seen from this evaluation is that DCOM and RMI are the distributed object middleware technologies with the best overall performance in terms of throughput and round trip time. Remoting-TCP generally generates the least amount of network traffic, while Remoting-HTTP generates the most amount of network traffic due to it's SOAP-formated protocol. / Detta magister arbete handlar om en prestanda analys av distribuerade objectorienterande mellanlagers teknologier. Dokumentet jämför prestandan på följande teknologier: CORBA, DCOM, RMI, RMI-IIOP, Remoting-TCP and Remoting-HTTP. Jämförelsen är i både server och klient perspektiv. / The authors can probably not be reached on the e-mail addresses given here or in the thesis. A simple search on any search engine will probably lead to valid an address. The reason for this is becouse the student mail is not a longterm address.