A systematic approach for heat integration into an eco-industrial park through an integrated trigeneration system is presented. The approach is based on a new superstructure formulated as a multiobjective mixed-integer nonlinear programming model, where intraplant and interplant heat exchange for the process streams is allowed, in addition to the energy integration into the utility system that is constituted by a steam Rankine cycle (to produce electric power and hot utility), an organic Rankine cycle (to recover waste heat and produce electric power), and an absorption refrigeration cycle (to recover waste heat and provide refrigeration). To run the utility system, several external heat sources (solar, fossil fuels, and biofuels) are considered, which impact the economic, environmental, and social objectives considered in the model. A systematic approach to tradeoff the objectives considered is presented. Two examples are presented, where the advantages of the integrated eco-industrial park are shown. (c) 2013 American Institute of Chemical Engineers AIChE J, 60: 213-236, 2014