Five bacterial strains capable of growing at the expense of resorcinol as a sole carbon source were isolated from soil by means of the enrichment culture method. Strain No. 138 with an ability to grow most abundantly on resorcinol was tentatively identified as Pseudomonas putida R1. Ammonium nitrate enhanced the production of cells with high resorcinol oxidizing activity. This activity did not decrease in the medium without addition of ferrous ion, even when the resorcinol was consumed completely. Enzymes to metabolise resorcinol in the strain were inducible. It was necessary to add 0.01－0.05% resorcinol before harvest in order to obtain a large amount of cells with high activity sufficient to oxidize the resorcinol. The resorcinol oxidizing system in the washed cells of the strain was induced in the presence of resorcinol and ammonium nitrate.