4-arylmethylidene-3-methylisoxazol-5(4H)-ones and 4-arylmethyl-idene-3-phenylisoxazol-5(4H)-ones have been synthesized in the one-pot three-component synthesis in the presence of Dowex1-x8OH as catalyst in water. The products have been obtained in high yields (90-95%) and proper reaction times (1-5 hours). This method has eco-friendly profile and operational simplicity.