A rapid scanning fluorometer is used to obtain fluorescence spectral data characteristic of bacteria which do not readily produce fluorescent pigments. The data is generated in the form of an array of fluorescence intensity as a function of multiple excitation and emission wavelengths. Fluorescence spectral properties are introduced into the bacterial specimen using multiple dye mixtures for staining. The characteristic fluorescent fingerprints are believed to occur by preferential adsorption and reaction of bacterial cellular components with the individual dyes of the mixture. The procedure is found to be rapid and reproducible for the bacteria examined.