In this work, we report a three-dimensional (3D) MoS2/rGO foam based sulfur cathode with improved electrochemical performance for lithium-sulfur batteries. The porous MoS2/rGO foam is prepared by a facile hydrothermal method. Few-layered MoS2 nanosheets with mixed 1T and 2H phases are developed in situ on the basal plane of the reduced graphene oxide (rGO), forming a continuous 3D porous network. It is found that the porous MoS2/rGO foam shows synergistic effects of high conductivity, large surface area, strong polysulfide chemisorption and high catalytic activity, consequently resulting in enhanced rate performance and cycling capability of lithium-sulfur batteries. The cells constructed with the MoS2/rGO/S cathodes exhibit a high reversible capacity of 1100 mA h g(-1) at 0.2 C, an outstanding cycling stability with a low capacity fading rate of 0.15% after 300 cycles at 1 C, and an excellent rate performance up to 620 mA h g(-1) at 2 C. Our work reveals that the porous MoS2/rGO foam based sulfur cathodes are potential for future high-performance lithium-sulfur batteries.