A simple, rapid and sensitive method for the analysis of dobutamine in equine arterial and venous plasmas was developed. After the addition of an internal standard samples were extracted using disposable, prepacked reverse phase colums. Samples were chromatographed at room temperature over a 15 cm 3 um C-18 column. Detection was by a glassy carbon electrode operated at 55 volts with respect to Ag/AgCl electrode. Using this method sensitivities of 100pg/ml (signal to noise; 3:1) were obtained. The applicability of the method is shown is anesthetized horses infused at 2.5, 5.0 and 0.5 μ/kg/ min.