The nylon oligomer (6-aminohexanoic acid cyclic dimer) degradation genes on plasmid pOAD2 of Flavobacterium sp. KI72 were cloned into Escherichia coli vector pBR322. The locus of one of the genes, the structural gene of 6-aminohexanoic acid linear oligomer hydrolase, was determined by constructing various deletion plasmids and inserting the lacUV5 promoter fragment of E. coli into the deletion plasmid. Two kinds of repeated sequences (RS-I and RS-II) were detected on pOAD2 by DNA-DNA hybridization experiments. These repeated sequences appeared five times (RS-I) or twice (RS-II) on pOAD2. One of the RS-II regions and the structural gene of the hydrolase overlapped.