Composites with polyvinyl chloride (PVC) as major matrix constituent, ethylene vinyl acetate (EVA) as polymeric plasticizer and wood flour (WF) and fly ash (FA) as filler were extruded. Morphology of the samples was studied using scanning electron microscopy (SEM). Morphological study indicated good dispersion of the constituents. Infrared spectroscopy (IR) indicates interaction between EVA and PVC and also between the polymeric matrix and WF. The effect of various constituents on glass transition temperature (T-g) was evaluated using differential scanning calorimetry. Addition of EVA decreased the T-g whereas T-g was increased due to addition of WF and FA. Study indicated that reduction in T-g on addition of EVA was compensated by increase in T-g due to addition of WF. The contribution of FA to change in T-g was not significant. Resulting composites have T-g close to that of PVC. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 114: 90-96, 2009