A new method for the rapid and simultaneous detection of ketamine and its major metabolite, norketamine, in rat hair has been developed by combining micropulverized extraction and ultraperformance liquid chromatography-electrospray ionization mass spectrometry. By using reversed-phase UPLC, ketamine and norketamine were well separated within 2 min. Using ketamine-dosed rat hair, the conditions for micropulverized extraction were optimized, and the limits of detection and quantification of the developed method were found to be 1.7 and 5.7 pg/mg hair for ketamine, respectively. The precisions achieved with this method were slightly better than that obtained with conventional acidic methanol extraction method. Using this proposed method, analysis of the washed rat hair could be completed within 16-17 min. This method is expected to be applied for the analysis of the hair samples of not only rats but also ketamine abusers.