In this paper we provide a comprehensive methodology for the specijication and design of broadband itiiiltitnedia telecoititiiitnicntion sewices rtith IN capabilities. Initiallv the key concepts of an integrated IN / B-ISDN architecture are presented aitning at the pro?!ision of novel rnultimedia features such as the coordination of different calls in (1 session (is well cis col1 / connection separation. The paper proposes alternative ways of producing IN service tnodels f rotti the prose description of the .semices. Consequently we examine the available optionsfor distributing service logic in the rarious netlcork nodes followed by o discussion on service data tables and the .specl/ication of message flows across intetfnces. Finally ci itiappin2 Jrortr a Joritid .service specification in SDL towards a an actual service design is provided by itieans of ci Service Creation and Sirnulation Environment. Throughout the paper two services are used for providing prtictical e.t.attiples oj' the proposed niethodologv : a Video on Demand (VoD) service which is a true IN .senlice and a Broadband Video Conjtrence Service (B-VC) which is based on an existing itnplementation originallv targetedfbr a TCP / IP network platjorrn.