The objective of this work is to determine mepivacaine hydrochloride (MPVHC) as local anesthetic drug. Modified carbon paste ion-selective electrode was used for the determination of MPVHC in different dosage forms and biological fluids. The study depends on potentiometric titration of MPVHC drug using modified carbon paste (MCPE) as end point indicator electrode. The effects of the paste composition, different conditioning parameters and foreign ions on the electrode performance were investigated and response time of the electrode has been studied. The results obtained showed that carbon paste electrode modified with sodium tetraphenyl borate-MPV ion pair gives the highest potential break at the end point, Nernstian slope, wide concentration range and lower detection limit than the reinckate-, phosphotungestic- and phosphomolybdic-MPV ion pairs. The fabricated electrode obtained Nernstian response of 57.71±0.67 mV decade-1 in the concentration range of 3.1×10-7 – 1.0×10-1 mol L-1 for MCPE electrode. The electrode was found to be operating within the pH range of 3.0–8.0 and exhibited a fast response time (about 14 s), low detection limit of 3.1×10-7 mol L-1 and long lifetime (98 days). The electrode showed high selectivity to the MPVHC drug in the presence of different organic, inorganic and amino acids. The electrode was successfully applied for the determination of MPVHC in pharmaceutical preparations and biological fluids (urine and plasma) with high percent recovery and low standard and relative standard deviation values. The results obtained applying this potentiometric electrode are comparable with British pharmacopeia. The method validation parameters were optimized and the method can be applied for routine analysis of MPVHC drug.