Thirty-seven (E)-1-(4-methyl-2-arylaminothiazol-5-yl)-3-arylprop-2-en-1-ones were synthesized via Claisen-Schmidt condensation of 1-(4-methyl-2-(arylamino) thiazol-5-yl) ethanone with the corresponding arylaldehydes. All these thiazolyl–chalcones were characterized and evaluated by MTT assay on human cancer cell lines BGC-823, PC-3, NCI- H460, BEL-7402 in vitro. Compounds 5, 8, 26, 37 and 41 are effective against cancer cell ...