Structural changes during fast drawing of poly(ethylene terephthalate) were studied by wide-angle X-ray scattering using synchrotron radiation. Drawing was studied at 80, 90, 100 and 110 degrees C to a final draw ratio of similar to 4:1 at a draw rate of similar to 10 s(-1). Simultaneous video recording of the sample enabled variation in the X-ray pattern to be correlated with local extension. Essentially all oriented crystallization occurred after final extension. Primary crystallization fits a first-order transformation with little change in the rate of crystallization observed over the 30 degrees C range of temperature. These results show that it can be misleading to rely on crystallinity information obtained when samples from interrupted draw experiments are quenched.