A series of triazencs derived from 5-(4-aminophenyl)-2,4-dihydro-4-substituted-3H-1,2,4-triazole-3-thiones 1a-c, aminoglutethimide or para-aminobenzoic acid have been synthesized for in vitro anticancer properties against three cell lines . The selected compounds; 1,3-bis[4(4-methly-2,4-dihydro-3H-1,2,4-triazole-3-thioxo-5-yl)phenly]-3H-triazene 2a, 1,3-bis[4(4-ethly-2,4-dihydro-3H-1,2,4-triazole-3-thioxo-5-yl)phenyl]-3H-triazene 2b,1,3-bis[4(4-allyl-2,4- dihydro-3H-1,2,4- triazole-3-thioxo-5-yl) phenyl]-3H-triazene 2c and 1-[(4-carboxy)phenyl]-3-[4(4-allyl-2,4-dihydro-3H,1, 2,4-triazole-3-thioxo-5-yl)phenly]-3Htriazene 4 show significant activity but not 1,3-bis[4-(3-ethyl-2,6-dioxo-3-piperidnyl)phenyl]-3H-triazene 3. 2a-c and 4 that pass the criteria for activity in this assay have been scheduled automatically for evaluation against the full panel of 60 human tumour Cell lines from leukemia, melanoma, lung, colon, kidney, ovary, breast, prostate and central nervous system cancer at a minimum of five concentrations at 10-fold dilutions. Sulphorhodamine B (SRB) protein assay has been used to estimate cell viability or growth. Compounds 2a-c and 4 show variable antitumor activity against most of the tested sub-panel tumor cell lines. The log(10)GI(50) values of these compounds are comparable to values of dacarbazine and mitozolamide based anticancer agents.