Electronic negotiation support aims at enabling complex trade interactions through means of information technology. Present research in electronic negotiation support is limited to a large extent to the analytical decision support view. There is a lack of empirical evidence on the acceptance of the different types of support in the negotiation support portfolio and their value contribution. In this paper, the results of a laboratory experiment evaluating the communication support feature of a particular negotiation support system, namely the Negoisst system, is presented. It is concluded, that dedicated communication support is highly relevant in users’ perception of usefulness.