Bacillus cereus, strain TS, was grown in 30-liter stirred fermentors on a complex medium. Pigment was isolated from the cells and converted to the free acid, which was identified as pulcherriminic acid. A procedure for the spectrophotometric assay at 410 mμ of pulcherrimin and pulcherriminic acid was developed to measure the maximum, but not necessarily absolute, degree of purity of samples of these compounds.