The effect of applying a heat treatment to polypropylene beverage cups on the physical structure of the material and on the migration of additives to food simulant D1 (ethanol 50 % v/v) has been studied. This treatment is sometimes carried out by laboratories prior to performing a migration test, but can also reflect the temperature of real storage conditions of food contact materials. Several cups were heat-treated at selected temperatures and either analyzed with differential scanning calorimetry to establish the degree of crystallinity or used for the migration test. Six target additives from Regulation (EU) No 10/2011 were quantified in the food simulant using HPLC-FLD and LC-MS. Results show that heat-treatment of the beverage cups led to a significant change in the degree of crystallinity, resulting in a change of analyte migration in comparison to the migration results from non-heat-treated cups.