In recent years, the chemistry of triazoles and their fused heterocyclic derivatives has received considerable attention owing to their synthetic and effective biological importance [1]. Literature survey reveals that 1,2,4-triazole derivatives exhibit a wide range of biological activities including Antibacterial, Antifungal, Antitumour, Anti-inflammatory, Antitubercular, Hypoglycemic, Antidepressant, Anticonvulsant, Anticancer, Antimalarial, Antiviral, Antiproliferative, Analgesic and Antimigraine [1,2]. The derivatives of 4-substituted-5(piridin-4-yl)-4H-1,2,4-triazole-3-thiol were synthesized according to scheme:schemeTable. The antiproliferative activity of 4-substituted-5-(piridin-4-yl)-4H-1,2,4-triazole-3-thiol on human on leukemia (HL-60) cells.tableThe obtained data demonstate that the synthesized compounds show moderate (3-11%) antiproliferative activity. Compounds e and d were tested on melanoma (MeW-164) and on human leukemia (HL-60) cells, in the range of (0,1-10 μM) concentrations. The results proved thait they have a higher (16-23%) antiproliferative activity.