Amino acid analysis (AAA) is widely used for determining the composition of proteins and their concentration in foods, biological fluids, and tissues. Because of the vast number of amino acids, the chromatographic techniques provide separations of them based either on the charge or on hydrophobicity differences. Several chromatographic techniques have been applied for this purpose, with the method of choice being ion-exchange chromatography followed by post-column derivatization, as a more rugged and reproducible method provides excellent amino acid separation with relative freedom from interferences. This review considers recent relative reviews, current separation techniques, the most popular post-column reactions for amino acid analysis, comparison with the pre-column methods, the... strategies used to develop effective post-column methodology, instrumentation technology, and applications in food and clinical analysis. The focus of the article is on liquid chromatographic methods coupled with post-column derivatization in order to increase sensitivity and selectivity, illustrating the versatility of the post-column derivatization (PCD) instrumentation for practical analysis.