This paper introduces an exact method to schedule the internal transshipment process at cross-docks in less-than-truckload industries. An integer programming formulation is presented to minimize the cost of double handling by synchronizing two types of decisions: (1) products' internal transferring route, and (2) the order of processing trucks at the terminal doors. Several valid inequalities are introduced to strengthen the formulation and to increase the efficiency of the proposed algorithm. A tailored branch and bound algorithm is developed. Several structural properties and a heuristic method are implemented to enhance the algorithm. Computational experiments of up to 40 trucks demonstrate the efficiency of the proposed approach. (C) 2017 Elsevier Ltd. All rights reserved.