A bacterium, strain YK 391 producing extracellular cytosine deaminase, has been isolated from soil sample collected near Taegu City and identified. The strain YK 391 was observed to be a motile Gram-negative rod, and did not produced capsule nor spore. The bacterium produced acid from glucose and trehalose, not from arabinose. Esculine was nto hydrolyzed. The isolate could grow anaerobically at 37$circ $C, but not at 4$circ $C. Palmitoleic and palmitic acids comprised over 80% of the fatty acid composition of the strain. The strain. The strain YK 391 was identified as Chromobacterium violaceum YK 391 based on its morphological and physiolohical characteristics, and on the fatty acid composition. The extracellular cytosine deaminase produced by Chromobacterium violaceum YK 391 is believed to be unique because it was active not only on cytosine and 5-fluorocytosine but also on cytidine.