A poly(vinyl chloride) (PVC) membrane potentiometric sensor was developed for the determination of anti-epileptic drug levetiracetam. For this purpose, levetiracetam-tetraphenylborate (LEV-TPB) ion-pair was synthesized and the synthesized ion-pair was used as ionophore in PVC membrane structures. The membrane composed of 3.0 % (w/w) LEV-TPB ion-pair, 32.0 % (w/w) PVC, and 65.0 % (w/w) o-nitrophenyloctylether (o-NPOE) was determined as the membrane with the best potentiometric properties. The developed sensor exhibited a linear response in the concentration range from 1.0x10(-5) to 1.0x10(-1) mol L-1 and had a detection limit of 6.31x10(-6) mol L-1. For this sensor, pH working range and response time were determined as 6.0-8.0 and & AP;25 s, respectively. The sensor displayed a good selectivity for levetiracetam in the presence of a number of common ionic species and some anti-epileptic drug. The proposed levetiracetam-selective sensor was successfully applied for the determination of levetiracetam in pharmaceutical drug samples which is used in the treatment of epilepsy.