Simultaneous detection of codeine (COD) and diclofenac (DCF) is of crucial importance as their overconsumption has recently been widely noticed. For this purpose, a biomimetic sensor (bi-MIP) is devised, and an electronic tongue is used to analyze water samples containing these drugs. Advantageous properties of a conductive polymer (methacrylic acid) and metallic nanoparticles (silver nanoparticles) were exploited to develop the bi-MIP sensor. Electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and differential pulse voltammetry (DPV) were used as electrochemical characterization techniques. The proposed bi-MIP sensor seems to be a promising tool for the analysis of drugs in water samples. The limits of detection for DCF and COD took individually were 0.01 µg/mL and 0.16 µg/mL, respectively. Due to cross-reactivity, a Voltammetric Electronic-tongue (VE-tongue) was used to perform simultaneous detection of both drugs in mineral water samples. Its responses were processed by principal component analysis (PCA), discriminant function analysis (DFA), and support vector machines (SVMs). First, all samples were well classified according to their enrichment type, with a success score of 78.90% for PCA, 89.99% for DFA, and 99.50% for SVMs. Secondly, the VE-tongue was able to differentiate samples containing both analytes at different concentrations. The results of this study reflect on the one hand the feasibility of simultaneous detection of two target analytes via a biomimetic sensor. On the other hand, they demonstrate the ability of a multi-sensor to classify water samples according to their type and level of contamination.