AbstractChloramphenicol (CAM), a broad‐spectrum antibiotic, is restricted by the European Union (E. U.) and many other countries from treating food‐producing animals due to its severe side effects. Therefore, the rapid and sensitive detection of CAM in food products is crucial. Herein, a simple metal‐free electrochemical sensor based on mesoporous carbons: mesostructured 3 from Korea (CMK‐3) and carbon nanocage, CKT (carbons from KIT‐5), are fabricated and used to detect and estimate CAM. The catalysts are well characterized by means of XRD, SEM, HRTEM, BET, XPS. The high specific surface area (770.4 m2 g−1), pore volume (0.984 cm3 g−1), and interconnected ion diffusion channels make CMK‐3 more advantageous than CKT, reflected in its rapid current response, higher sensitivity, and selectivity towards CAM. In the electrochemical determination process using cyclic voltammetry (CV), CMK‐3 shows a better response than bare glassy carbon electrodes and CKT. Moreover, at optimum conditions, the synthesized electrochemical sensor CMK‐3 exhibits a lower limit of detection and limit of quantification values of 3.3 μM and 11.1 μM, respectively, with a sensitivity of 6.9 A μM−1 cm−2. Moreover, the proposed sensor is also utilized for CAM detection in real samples like milk and eye drop with appreciable selectivity and satisfactory recovery of 90.5–98.68 % for milk and eye drop samples.