In this paper a Web-based Negotiation Support System CBSS is introduced. The system facilitates a structured on-line negotiation process. It is written in JAVA language and can be accessed easily through the Web. The system has been tested in comparison with face-to-face meetings in stimulated labour union-management negotiations. The test shows that CBSS was viewed as a valid alternative to face-to-face negotiation, although bargaining processes supported by CBSS were perceived to be slower than face-to-face negotiation.