CD4+CD25+FoxP3+ T-regulatory (Treg) cells are vital to the maintenance of peripheral self tolerance and are implicated in tolerance to foreign antigens. Increasing evidence shows that Treg cells may also play an important role in immune evasion mechanisms employed by cancer. Treg cells are actively recruited and induced by tumors to block innate and adaptive immune priming, effector function and memory response, which can inhibit the efficacy of therapeutic cancer vaccines. As such, modulation of Treg cell function in cancer has been studied using various approaches, with encouraging preclinical and clinical findings. However, controlled and effective modulation of Treg cell function for cancer therapeutics will be contingent on a better understanding of the molecular basis of Treg cell interaction with tumor cells and ensuing immunosuppressive mechanisms.