Baking powder is widely used to leaven baked products. The industry standard for baking powder shelf-life is eighteen to twenty-four months, but little information is available on baking powder functionality when stored beyond this time. A longer shelf-life would prove beneficial in certain situations, such as personal food storage, disaster relief efforts, and space missions. The objective of this research was to determine the effect of long-term storage on baking powder functionality. Six samples of double-acting baking powder in original commercial packaging were obtained from donors and two fresh samples were purchased. Samples ranged in age from 0.25-29 years and were stored in cool (15-25º C) and dry conditions. Percent moisture was determined gravimetrically. Baking powder samples were reacted with 100% phosphoric acid in a closed vessel and the total carbon dioxide evolved was measured using a CO2 extraction line. Biscuits were made following standardized procedures and measured for height, diameter, and surface crumb color. Moisture content of baking powder samples ranged from 1.4-3.2%. Total CO2 ranged from 18.8-21.9% of sample weight and did not significantly decrease over storage time. Average biscuit heights ranged from 3.0-3.4 cm, with the control made without baking powder averaging 2.1 cm. The average volumes (calculated from the average measured heights and diameters) ranged from 66-79 cm3, with the control averaging 47 cm3. Average height and volume did not decrease over storage time. Mean L*a*b* color values for biscuits ranged from 66.0-70.5, 4.0-7.4, and 25.9-31.2, respectively, with control biscuits averaging 70.6, 1.5, and 18.6, respectively. Under optimal storage conditions, it appears that baking powder retains its functionality as a leavening agent for many years and can be included in applications requiring long-term food storage.