Summary o 1. Acidic and neutral amino acids can be chromatographed selectively on a22-cm column of spherical resin using the Beckman-Spinco amino acid analyzer. Four procedures will elute four different groups of amino acids, each with satisfactory resolution of the individual amino acids. Only the regular buffers, or simple modifications thereof, and regular operating conditions are used for these accelerated procedures. 2. Amino acids in physiological fluids can be analyzed quantitatively over a concentration range of 0.01–0.2 umoles ; the accuracy is equivalent to that obtained on the 55-cm resin column. Accelerated chromatography can therefore be used for the investigation and management of patients with disorders of acidic and neutral amino acid metabolism. 3. Simple, economical mechanical modifications of the analyzer are alsodescribed whereby two resin columns may be eluted and analyzed simultaneously, thus further increasing the efficiency of analyzer operation.