Many pharmaceutical materials exhibit polymorphism, and depending upon the given processing conditions, the crystalline form may exist in two or more states. The existence of these polymorphic crystalline states is important for many pharmaceutical materials, as they can have a major effect upon the uptake of the active drug into the bloodstream once ingested and the shelf life of the drug. Differential scanning calorimetry (DSC), particularly power compensated DSC, has proven to be an extremely valuable technique for the characterization of polymorphism in pharmaceutical materials. This application note describes how the PerkinElmer DSC 8500 provides high sensitivity and unsurpassed resolution necessary to detect polymorphism exhibited by many pharmaceutical materials.