An improved procedure is presented for the direct photometric estimation of free amino acids on small-scale filter paper chromatograms. The estimation of total spot density is facilitated by a device for mounting the paper chromatograms in the sample chamber and in front of the photocell of the photometer. Complete amino acid assays are obtained within a 24-hour period. The assay range is 0.1 to 1.0Ü3 for solutions containing as little as 150Ü3 per ml. Values are presented for alanine, Ü3-aminobutyric acid, arginine, aspartic acid, glutamic acid, and proline in the filtered juices of California Valencia and Washington Navel oranges.