Mechanical properties of melt-spun and postdrawn isotactic polypropylene (iPP) are studied to examine the dependence on the temperature in the postdrawing stage. In accordance with the literature, the Young's modulus is uniquely determined by the applied draw ratio. However, in contrast to the literature, we found that the overall mechanical behavior strongly depends on the applied postdrawing temperature. For a fixed draw ratio, a significant drop in yield stress can be observed with decreasing drawing temperature. At a certain drawing temperature, this drop leads to a transition from brittle to ductile failure behavior. From this study it can be concluded that a proper choice of drawing conditions offers control on several mechanical properties (e.g., stiffness, strength) at the same time.