A number of 4-arylamino-3-(trifluoromethyl)pyridazines were obtained in good yields via the novel reaction of 3-aroylmethyl-2-(trifluoromethyl)quinoxalines with an excess of hydrazine hydrate in refluxing n-butanol with or without acetic acid. This reaction is accompanied by the formation of side-products with the pyridazino[3,4-b]quinoxaline skeleton. The possible reaction mechanism was discussed.