A multitechnique analysis approach has been used to study the bulk and surface properties of a biodegradable copolymer produced from agricultural feedstocks. The sample analyzed is a thermoplastic copolyester commercialized under the trademark Biopol that contains beta-hydroxybutyrate (HB) and beta-hydroxyvalerate (HV) units incorporated randomly throughout the polymer chain. The techniques applied are gas chromatography mass spectrometry (GC-MS), nuclear magnetic resonance spectroscopy (NMR), differential scanning calorimetry (DSC), time-of-flight secondary ion mass spectrometry (TOF-SIMS), and X-ray photoelectron spectroscopy (XPS). Special emphasis is put on the quantitative determination of the surface composition of the copolyester by TOF-SIMS and XPS as well as the analysis of the molar bulk fraction by NMR and DSC.