Two bacterial strains essential for polyvinyl alcohol(PVA) degradation were isolated from an efficient PVA utilizing mixed culture which had been selected by screening experiments with approximately 240 samples from soils and other environmental sources. The two strains were almost unable to grow on the PVA minimal medium in each respective pure culture but the mixed culture of the two strains was found to grow symbiotically and to utilize PVA efficiently as a carbon and energy source. The two symbionts, designated KMG1 and KMG5, were identified as Pasteurella haemolytica and Psudomonas sp., respectively. The Psudomonas sp. KMG5 was confirmed to be an actual PVA degrader and the other symbiont KMGI was presumed to supply the degrader with some kind(s) of growth stimulant. In the mixed culture, the bacterial symbionts utilized almost completely 0.5% PVA at 37℃ in 7 days.