Instant Messaging (IM) has the potential to become one of the killer applications for interactive Digital Television (iDTV) [12]. However, several factors make it difficult to provide a good implementation of IM services, among which the limited resources of a settop box and the different user experience compared to computer environments. This paper proposes the XMPP (Extensible Messaging and Presence Protocol) standard as a solution for implementing IM. When we compare XMPP with other technologies, it reveals itself to be very well adapted to the specific needs of iDTV middleware platforms like the Multimedia Home Platform (MHP) [5]. Moreover, the use of XMPP doesn’t limit itself to IM. The flexible architecture of XMPP opens a window of opportunities like the ease of adding new interactive services. To demonstrate the possibilities of XMPP on MHP, an IM client –IM4MHP– is presented in this paper.