A liquid membrane electrode based on metomidate - dipicrylamine ion-pair complex, dissolved in nitrobenzene as solvent is proposed for the determination of metomidate - an anesthetic drug. The linear response covers the range from 10−2- 10−6M metomidate solution, with a slope of 55.98 mV/decade (pH range 1.75 to 4.50). The detection limit is 3.31 × 10−9M. The electrode shows stability, good reproducibility and fast response. The selectivity of the electrode is also good with the exception of mianserin which is strong interfering ion. These characteristics of the electrode made it useful for the determination of metomidate through direct and indirect potentiometric methods. Through indirect determined potentiometric method, metomidate can be determined with an average recovery of 98.52% and a relative standard deviation of 0.93%.