Summary: An electrochemical sensor was developed by electropolymerizing aniline on a glassy carbon electrode in a nonaqueous medium and modifying it with multi-walled carbon nanotubes (MWCNTs). This sensor enabled the quantitative determination of levodopa and benserazide, key drugs for Parkinson’s disease treatment. The optimized method demonstrated high selectivity and sensitivity, with detection limits of 67.01 µM for levodopa and 163.60 µM for benserazide. The sensor performed well in real urine samples and pharmaceutical formulations, even in the presence of interfering species.