Cold-adapted (psychrotolerant and psychrophilic) microorganisms are distinguished from mesophiles by their ability to grow at low temperatures. They are widely distributed in nature and they have evolved a complex range of adaptations enabling them to grow and survive in cold environment. Adaptation changes include both enzymes present in the microorganisms and lipids forming cell membranes. Due to their unique properties, cold-active enzymes are used in several biotechnological applications (detergents, biotransformations, contact lens cleaning, hydrolysis of lactose in milk). Of the lipids, polyunsaturated fatty acids serve as dietary supplements in food industry. Current knowledge of cold-adapted microorganisms indicates their high biotechnological potential for the future.