Procaine belongs to a type of medicine that excessive dosage creates cardiac arrest and also several allergenic reactions. Thus, continuous monitoring of the drug and its metabolite is necessary for sustainable health management during treatment. The innovative aspect of nanostructure materials has great importance in the advancement of research on modified sensors. In the present study, the electrocatalytic performance of multi-walled carbon nanotubes modified carbon paste electrode was investigated for the simultaneous analysis of procaine hydrochloride and p-aminobenzoic acid with high accuracy and sensitivity. The nanostructured sensor is characterized by microscopic and electrochemical techniques, such as scanning electron microscopy and electrochemical impedance spectroscopy using [Fe(CN)6]3-/4- as the redox probes. The modified sensor shows an improved voltammetric peak current than the unmodified carbon paste electrode. The electrochemical behavior of the modified sensor was studied by cyclic voltammetry and differential pulse voltammetry. The sensor kinetic parameters containing electron transfer rate constant (ks=0.47 s-1) and charge transfer coefficient (α=0.23) were calculated using cyclic voltammetry. The differential pulse voltammetry technique was also investigated in terms of linearity, lower limit of detection, lower limit of quantitation, accuracy and precision, which indicate acceptable results. Under optimized experimental conditions, the concentration linear range for procaine and PABA was obtained in the range of 2.4 to 100.0 µM. The limit of detection values (S/N=3) were calculated to be 62.0 and 49.0nM for detection of procaine and p-aminobenzoic acid, respectively. Also, the effects of interfering materials, repeatability and stability of the modified sensor were studied. Finally, the proposed sensor was applied for simultaneous and sensitive detection of p-aminobenzoic acid and procaine in real media such as plasma and pharmaceutical products with satisfactory results.