Résumé : The analysis of non-discrimination under Article III of GATT has shown weakness or flaws throughout more than fifty years. The language used by GATT/WTO panels and the Appellate Body in interpreting the two prongs of non-discrimination in the national treatment clause, namely, likeness and protection, lagged behind economic reality. The critical legal analysis carried out in here reveals, to some extent, this while offering a clearer and sounder analysis to non-discrimination based more on market analysis and its economic indicators.