The purposes of this study were to characterize the pharmacokinetics (PK) of hydrochlorothiazide (HCT) in camels and to develop a sensitive liquid chromatog. tandem mass spectrometry (LC/MS/MS) method for the detection of HCT in camel fluids and to advice on a withdrawal period before camel racing following a therapeutic dose of HCT.Hydrochlorothiazide resulted in profound urine production in camels but no adverse effects were observedThe AUC0-∞ of the double dose was twice that of the first dose and was significantly different from it.However, Vss, CIT, T1/2β and mean residence time were similar in both dose regimens suggesting linear kinetics in the dose range used.The LC/MS/MS method used in this study proved to be sensitive and efficient and is superior to HPLC methods that lacked sensitivity and to GC, and GC/MS methods which required cumbersome derivatization steps.He LC-MS/MS method reported in this study, with a LOQ of 2 ng/mL, could easily detect HCT 1-2 days after administration.Therefore, as a precautionary measure due to inter-animal variation, we propose withholding HCT administration before racing for a min. period of 3 days.