We have developed a series of six CTL lines exhibiting preferential killing of autologous tumour cells from tumour-associated lymphocytes (TALs) infiltrating malignant ovarian ascites. Five out of six CTL lines showed increased percentages of V beta 8.1+ cells, four showed increased percentages of V beta 5.3+ cells and one showed increased percentages of V beta 6.7+ cells. On the contrary, fresh isolated TALs or autologous PBMCs, when stimulated by OKT3 mAb or other TAL cultures with nonspecific cytolytic function, did not show preferential usage of any of these families. Most important, V beta 8.1+ and V beta 6.7+ T cells within the CTL-TALs mediated cytoxicity against autologous targets. This represents the first demonstration of preferential usage of TCR V beta in ovarian tumor-specific CTLs and suggests possible association between tumor surveillance and TCR V beta genes.