The combined effect of temperature and thickness on the essential work of fracture (EWF) parameters for an unplasticized. poly(vinyl chloride) (uPVC) film was investigated using double edge notched tension specimens. It was found that for the range of temperatures (23degreesC to 60degreesC) and thicknesses (0.15 mm to 0.40 mm) studied here, specific essential work of fracture (w(e)) was independent of temperature at each thickness but increased with thickness at each temperature. It was found that at each temperature. w(e) and its yielding (w(e,y)) and necking/tearing components (w(e,nt)), all increased linearly with increasing thickness. However, whilet w(e) showed no significant variation with respect to temperature, its yielding component (w(e,y)) decreased and its necking/tearing component increased (w(e,nt)) with increasing temperature. It was found that estimated values of w(e) and its components w(e,y) and w(e,nt) via crack opening displacement values were by and large unsatisfactory, being either much higher or lower than the directly measured values.