Thirty tumour specimens, among which were 17 melanomas, were cultured with recombinant interleukin-2 (IL-2) in order to produce tumour-infiltrating lymphocytes (TIL). In the melanomas, three categories of TIL were characterised. The first, containing mostly CD3+ and CD8+ cells, lysed only autologous tumour cells; the second, containing mostly CD3+ and CD4+ cells, lysed both autologous tumour cells and allogeneic cells lines; the third, with mixed phenotype although cytotoxic for K562 targets, did not kill melanoma cells. The optimal conditions for a good development of TIL were established: we found that the lymph node or cutaneous origin of the tumour was unimportant, a 2 h enzymatic treatment was optimum and that TIL grew well in AIM V serum free medium. Therefore the easiness and the reproducibility of the TIL cultures from melanoma tumour samples allows the rapid development of therapeutic trials in metastatic melanoma.