Polymers containing cyclohexyl units were isolated when Pseudomonas oleovorans was grown with 5-cyclohexylvaleric (CHV) or 4-cyclohexylbutyric acid(CHB). This was opposed to the case where shorter chain acids were used as carbon sources. Growth experiments using homologous cycloalkylalkanoic acids as carbon sources were carried out with varying ratios of the acids to nonanoic acid. A concentration of 90% CHV (20 mM total concentration) afforded a polymer in which monomeric units containing a cyclohexyl ring (up to 24% of units) were identified by NMR and GC-MS. The polymeric material isolated in about 9% of the dry cell weight was a beige, sticky material similar in texture to poly(3-hydroxynonanoate). The polymer’s intrinsic viscosity was 0.77 dL/g, and its weight-average molecular weight 52000, as determined by GPC. Thermal analysis indicated the presence of two T-g values : T-g1 = -16.3 degrees C and T-g2 = -32.6 degrees C, which suggest the presence of two polymers, one containing more cyclohexyl rings than the other. This observation was sustained by TLC analysis.