Cancer immunotherapy using the adoptive transfer of autologous tumor-infiltrating lymphocytes results in objective cancer regression in 49-72% of patients with metastatic melanoma. In a pilot trial combining cell transfer with a maximum lymphodepleting regimen, complete durable responses were seen in 40% of patients, with complete responses ongoing beyond 3 to 7 years. Current approaches to cell transfer therapy using autologous cells genetically engineered to express conventional or chimeric T-cell receptors have mediated cancer regression in patients with metastatic melanoma, synovial sarcoma, neuroblastoma and refractory lymphoma. Adoptive cell transfer immunotherapy is a rapidly developing new approach to the therapy of metastatic cancer in humans. This Review will emphasize the current available applications of cell transfer immunotherapy for patients with cancer.