PVDF cast films were drawn at different temperatures to different draw ratios at constant draw rate to understand the mechanism of alpha to beta phase transformation during mechanical deformation. WAXD and FTIR studies were carried out to determine the formation and content of beta phase in the drawn films. Lower stretch temperatures gave higher fractions of beta phase. The cast PVDF films were also drawn at suitable temperatures below the PVDF ambient melting point to the draw ratio of 6.4. The highest fraction of beta phase obtained in these ultra drawn films was 0.98. SALS studies carried out for films at different stretch ratios show the change in spherulitic structure with the stretching parameters and give information for the understanding of phase transformation during stretching of PVDF films. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 117: 3491-3497, 2010