The purpose of this study was to predict the shelf life of an infant formula using accelerated stability tests to save time. The stability of two infant formulas (a commercially available infant formula and the same infant formula supplemented with microencapsulated fish oil) was followed throughout 18 months of storage at room temperature and for 20 days stored at 60 degrees C by measuring the peroxide value. Stability was also measured using an accelerated stability test (Rancimat) at different temperatures (60, 80, 90, 100, 110, 120, or 130 degrees C). An equation has been derived by which shelf life can be predicted on the basis of the results of accelerated stability tests and therefore saving time.