4-Aryl-1, 8-naphthyridin-2 (1H)-on-3-yl urea derivatives with hydrophilic groups were synthesized in order to improve aqueous solubility and pharmacokinetic property. SMP-797 possessing (4-aminophenyl) ureido and 3-(hydroxypropoxyphenyl) moieties showed potent ACAT inhibitory activity and excellent oral efficacy.