Poly(3-hydroxyalkanoate) (PHA) with a thiophenoxy group at the end of the side chain was obtained from Pseudomonas putida 27N01, using 11-thiophenoxy undecanoic acid as the sole carbon source. NMR and GC/MS analyses indicated that the polymer consisted of 3-hydroxy-5-thiophenoxypentanoate as the primary monomer unit and 3-hydroxy-7-thiophenoxyheptanoate as a minor unit. The polymer had a white cream color and was elastometric. X-ray analysis suggested that the PHA had an amorphous-like diffraction pattern. The final dry cell concentration was 693 mg/L, and the PHA content of the dry cells was 19.5%. GPC measurement with polystyrene as a standard showed that the number-average molecular weight was 81 000 with a polydispersity of 1.8. The glass transition temperature was approximately 4 degrees C according to DSC. Thus, we were able to successfully characterize this PHA and to show that a sulfur atom can be incorporated into the bacterial polymer produced from P. putida 27N01.