A series of novel pyrimidin-4(3H)-one hydroxamate derivatives was designed, synthesized and studied for their activities against histone deacetylases(HDACs). The results indicate that all the compounds show HDACs inhibitiory activity. The antiproliferative activities of the compounds against HeLa and A549 cells were also investigated. The pharmacological results show compound 9g has potent activity in the enzymatic inhibition assay and cell-based assay.KeywordsHistone deacetylasesAntitumor acitivtyPyrimidin-4(3H)-one hydroxamate derivative