Cetuximab(CTX) is a potent chimeric mouse/human monoclonal antibody(mAb) approved worldwide for treatment of metastatic colorectal cancer. Among the various biological and physical analyses performed for full study on this biopharmaceutic, the determination of the concentration preparations throughout manufacturing and subsequent handling in hospital is particularly relevant. In the present work, the study and validation of a method for quantifying intact CTX by reverse-phase high-performance liquid chromatography with diode array detection((RP)HPLC/DAD) is presented. With that end,we checked the performance of a chromatographic method for quantifying CTX and conducted a study to validate the method as stability-indicating in accordance with the International Conference on Harmonization guidelines(ICH) for biotechnological drugs; therefore, we evaluated linearity, accuracy, precision, detection and quanti fication limits, robustness and system suitability. The speci ficity of the method and the robustness of the mAb formulation against external stress factors were estimated by comprehensive chromatographic analysis by subjecting CTX to several informative stress conditions. As demonstrated, the method is rapid, accurate, and reproducible for CTX quantification. It was also successfully used to quantify CTX in a long-term stability study performed under hospital conditions. Among the various biological and physical analyzes performed for full study on this biopharmaceutic, the determination of the concentration of product throughout manufacturing and subsequent In the present work, the study and validation of a method for quantifying intact CTX by reverse-phase high-performance liquid chromatography with diode array detection ((RP) HPLC / DAD) presented. With that end , we checked the performance of a chromatographic method for quantifying CTX and conducted a study to validate the method as stability-indicating in accordance with the International Conference on Harmonization guidelines (ICH) for biotechnological drugs; therefore, we evaluated linearity, accuracy, precision, detection and quanti fication limits, robustness and system suitability. The speci ficity of the metho d and the robustness of the mAb formulation against external stress factors were estimated by full chromatographic analysis by subjecting CTX to several informative stress conditions. CTX in a long-term stability study performed under hospital conditions.