Naturally occurring CD4(+)CD25(+) regulatory T cells (Tregs) expressing forkhead transcript factor box P3 have been established as a key regulator for the control of autoimmunity. A growing body of experiments in animal models has provided compelling evidence that the adoptive transfer of CD4(+)CD25(+) Tregs can cure many autoimmune and allergic diseases, and appear to induce donor-specific transplantation tolerance. Thus, customer-tailored CD4(+)CD25(+) Tregs have emerged as potential reagents for adoptive cell therapy for individualized medicine. This review discusses recent advances towards that goal.