We propose a framework to compute the utility of a proposal \wrt a preference set in a negotiation process. In particular, we refer to preferences expressed as weighted formulas in a decidable fragment of First-order Logic. Specifically, we refer to expressive Description Logics (DL) endowed with disjunction. DLs offer expressivity advantages over propositional representations, and allow us to relax the often unrealistic assumption of additive independence among attributes. We provide suitable definitions of the problem and present algorithms to compute utility in our setting. We also study complexity issues of our approach and demonstrate its usefulness with a running example in a multiattribute negotiation scenario.