A series of 2-substituted imidazo[1,2-a]-1,3,5-triazines with various aliphatic and aromatic amines has been prepared and characterized by IR,1H-NMR, and elemental analysis. The initial in-vitro cytotoxicity studies with five human cancer cell lines showed that all but one of the compounds are without cytotoxic activity. The one active compound, 2-(indolin-1-yl)-7,8-dihydroimidazo[1,2-a]-1,3,5-triazine-4(6H)-thione 12, was tested on 12 human cancer cell lines. Of these, two lines, RT-4 and MCF-7, were the most sensitive to the compound, with IC50 values of 6.98 microM and 8.43 microM, respectively. When compared with the reference anticancer drug 6-mercaptopurine, only the RT-4 urinary bladder and KYSE-70 oesophagus cancer cell lines were more sensitive to the new compound. The antimetabolite thioguanine was more cytotoxic than 12 for all common cell lines tested.