The current concept of “Adoptive T Cell Immunotherapy of Cancer” is quite different from how it was originally conceived. With the development of modern technology in molecular biology, cell biology, immunology and biochemistry during the last twenty years or so, adoptive immunotherapy has grown from its initial form of a simple “blood cell transfer” into its present process which involves host vaccination, effector cell activation/polarization and genetic modification. With the use of immune adjuvants and the identification/characterization of tumor-reactive T cell subsets, or in combination with other therapeutic strategies, adoptively transferred T cells have become much more potent in mediating tumor regression. In addition, studies on the trafficking of infused T cells, cell transfer performed in lymphopenic models, as well as the discovery of novel techniques in immune monitoring for the generation of effector cells in vitro and after cell transfer in vivo have provided useful tools to further improve the therapeutic efficacy of this approach. This article will review these related aspects of adoptive T cell immunotherapy of cancer with specific comments on certain critical areas in the application of this approach. With the rapidly evolving advances in this area, it is hoped that this cellular immunologic therapy as it was conceptualized in the past, can become more useful in the treatment of human cancer in the near future. The current concept of “Adoptive T Cell Immunotherapy of Cancer ” is quite different from how it was originally conceived. With the development of modern technology in molecular biology, cell biology, immunology and biochemistry during the last twenty years or so, adoptive immunotherapy has grown from its initial form of a simple “blood cell transfer” into its present process which transports host vaccination, effector cell activation / polarization and genetic modification. With the use of immune adjuvants and the identification / characterization of tumor-reactive T cell subsets, or in combination with other therapeutic strategies, adoptively transferred T cells have become much more potent in mediating tumor regression. In addition, studies on the trafficking of infused T cells, cell transfer performed in lymphopenic models, as well as the discovery of novel techniques in immune monitoring for the generation of effector cells in vitro and after cell transfer in vivo have provided u seful tools to further improve the therapeutic efficacy of this approach. This article will review these related aspects of adoptive T cell immunotherapy of cancer with specific comments on certain critical areas in the application of this approach. With the rapidly evolving advances in this area, it is hoped that this cellular immunologic therapy as it was conceptualized in the past, can become more useful in the treatment of human cancer in the near future.