The microfocus X-ray beamline at the European Synchrotron Radiation Facility has been used to investigate the variation in molecular orientation and crystallinity in spherulites of the organic polymer poly-3-hydroxybutyrate (PHB). This is the first report of the correlation of optical and X-ray measurements on spherulitic polymer films where X-ray diffraction patterns have been recorded and displayed continuously in real time while the specimen was tracked in steps of 10 mum across an incident X-ray beam with a diameter as small as 10 mum.