This paper generalizes the network utility maximization (NUM) model to a multiutility framework model using multiobjective optimization. It applies this framework to study the tradeoff between network utility and lifetime in wireless sensor networks (WSNs). The proposed approach approximates the Pareto front of the proposed model first and then uses the extended Lagrange duality to implement a particular solution selected by a decision maker from the Pareto front. Experimental results have demonstrated the effectiveness of this approach.