The secrets of longevity are recently being correlated with the functional benefits of food consumed in terms of its antioxidant activity, probiotics, and bioactives present in food. Scientific studies have provided evidence for the beneficial effects of these bioactives in enhancing immunity and preventing various diseases. Freeze-drying is a sophisticated technology based on the principle of sublimation of water present in foods, resulting in high-quality food with maximum retention of original taste, color, and bioactive compounds. These functional foods offer health benefits beyond nutrition. This chapter focuses on the mechanism of freeze-drying and its applications in development of functional foods. The categories presented are freeze-dried fermented foods, probiotic foods, antioxidant-rich foods, energy drink mixes, and performance-enhancing foods in convenient, lightweight form with long shelf life and functional properties, attributed to the advantages of freeze dehydration process. A summary of products in these categories, currently available in the market, is also given for the reader to have knowledge of advancements in this area.