Forty strains of bacteria and 60 of fungi were screened with globulol, 1,8-cineol and cedrol and the strains compared, on the basis of the resulting products, using multivariate analyses. The taxonomic position of the strains is mirrored in their biotransformation capability. Fungi and bacteria, fungal phyla, and Gram-positive and-negative bacteria could all be distinguished in a discriminant analysis using 12 substrates. Hierarchical clustering yielded five groups of strains with distinct biotransformation activity. Such clustering will allow a more efficient screening than before.