In order to improve the productivity of poly(3-hydroxybutyrate)[P(3HB)], Alcaligenes eutrophus was metabolically engineered to amplify the activities of the three enzymes involved in the synthesis of P(3HB). The A. eutrophus P(3HB) biosynthesis genes coding for P(3HB) synthase, β-ketothiolase, and reductase were cloned into a broad-host-range plasmid pVK101. Recombinant A. eutrophus strain was developed by transforming with this plasmid by electroporation. The efficiency of transformation was in an order of 10³ transformants/μg DNA. In flask cultures, the final cell concentration of recombinant A. eutrophus decreased with increasing carbon/nitrogen(C/N) molar ratio. On the other hand, P(3HB) concentration was highest at the medium C/N molar ratio. For the fixed nitrogen concentration, the concentrations of cell and P(3HB) increased with increasing glucose concentration. Comparison of cell growth and P(3HB) production by recombinant and wild type A. eutrophus in batch culture showed that the final P(3HB) concentration, P(3HB) content, and P(3HB) synthesis rate were all higher in the recombinant strain compared with the wild type.