The aim of the ISAAC (Integrated System Architecture for Advanced Primary Care) project is to develop information technology and telematic support in the Primary Health Care field. The project aims at describing the tasks and activities performed by General Practitioners throughout Europe and at improving their work through the development of a useful and usable medical workstation for day-to-day patient care. Moreover ISAAC has designed and implemented an Integration System for the improvement of the communications between General Practitioners and heterogeneous pre-existing application environments, namely other components of the health care system.