This study presents the electrochemical sensing of cadmium (Cd²⁺) and lead (Pb²⁺) ions in water using MOF-5/polyaniline (PANI) composites. The composites, prepared with PANI in its conducting (emeraldine salt, ES) or non-conducting (emeraldine base, EB) forms, were evaluated as electrode materials for detecting Cd²⁺ and Pb²⁺ ions. The MOF-5/EB-1 composite, containing 71.0 wt.% MOF-5, exhibited the highest oxidation currents for both ions, with detection limits of 0.077 ppm for Cd²⁺ and 0.033 ppm for Pb²⁺. The composite showed excellent electrocatalytic activity for the oxidation of Cd and Pb to their respective ions, with well-defined peaks in voltammograms obtained from real water samples, such as the Danube River, without pretreatment. The synergistic effect of MOF-5 and PANI was highlighted, where MOF-5 provides a high surface area for metal ion adsorption, while PANI facilitates electron transfer during oxidation. The MOF-5/PANI composites demonstrated high sensitivity, selectivity, and stability, making them promising candidates for electrochemical sensors in environmental monitoring. The results indicate that these composites could be effectively used for the detection of heavy metal ions in real water samples.This study presents the electrochemical sensing of cadmium (Cd²⁺) and lead (Pb²⁺) ions in water using MOF-5/polyaniline (PANI) composites. The composites, prepared with PANI in its conducting (emeraldine salt, ES) or non-conducting (emeraldine base, EB) forms, were evaluated as electrode materials for detecting Cd²⁺ and Pb²⁺ ions. The MOF-5/EB-1 composite, containing 71.0 wt.% MOF-5, exhibited the highest oxidation currents for both ions, with detection limits of 0.077 ppm for Cd²⁺ and 0.033 ppm for Pb²⁺. The composite showed excellent electrocatalytic activity for the oxidation of Cd and Pb to their respective ions, with well-defined peaks in voltammograms obtained from real water samples, such as the Danube River, without pretreatment. The synergistic effect of MOF-5 and PANI was highlighted, where MOF-5 provides a high surface area for metal ion adsorption, while PANI facilitates electron transfer during oxidation. The MOF-5/PANI composites demonstrated high sensitivity, selectivity, and stability, making them promising candidates for electrochemical sensors in environmental monitoring. The results indicate that these composites could be effectively used for the detection of heavy metal ions in real water samples.