This article presents a methodology that uses the continuum approximation approach to formulate the logistical problem of determining the number and location of recycling centers to which individuals in a region can deliver solid wastes to be recycled. To solve the proposed problem a two-stage approach is proposed. First, we solve an optimization problem whose main decision variable is the density of recycling sites per unit area. This problem is solved assuming that local conditions are similar throughout the region of interest. So, this problem is solved for each point of a grid that divides the region under study, yielding an optimal solution that reflects an approximation of the local optimum density. In the second stage, the solution is refined by identifying specific locations in which recycling centers could be installed, in a manner consistent with the approximate solution obtained in the first stage. Finally, this proposed approach is tested in a case study using data from Santiago, Chile. (C) 2016 Published by Elsevier B.V.