Fortification of foods with vitamins has become increasingly common. However, further studies on the stability of vitamins in foods are required because these compounds can easily degrade. The objective of this study was to evaluate the stability of ascorbic acid (AA; vitamin C) in fortified gelatin after dissolving the powder in water at room temperature (25 °C), after preparing the jelly according to label instructions, and after storing the ready-to-eat product for three days in the refrigerator, comparing the obtained values to those stated on the label. AA was measured by iodometry using an automatic potentiometric titrator with a platinum ring electrode. The AA contents of all the samples dissolved in cold water were either equal to or above those stated on their labels. However, the AA contents of two of the prepared and stored samples were below their stated label values, confirming AA degradation.