Using a new isolate of Pseudomonas aeruginosa, we obtained 7 g cell dry wt (CDW/l) using 5 % (w/v) glucose. Crude polyhydroxyalkanoates were obtained at 14.6 % of CDW. FTIR and NMR analysis confirmed that this was a new co-polymer: 3-hydroxyvalerate-co-5-hydroxydecenoate. Differential scanning calorimetry analysis showed two different melting temperatures of the copolymer and also indicated the glass transition temperature to be 4 A degrees C. The polydispersity index of the polymer was 1.059.