The sugars α-glucose, β-glucose, fructose, galactose, and sucrose were identified in the juice of Israel orange, grapefruit, and lemon by gas-liquid chromatographic methods. Rhamnose, xylose, and trehalose were also identified but only tentatively. The amounts of glucose and fructose before and after hydrolysis were measured in 88 samples of citrus juice by enzymatic methods. The concentration of glucose found was in all cases very near that of fructose. In other fruit juices (e.g., pear) the concentration of fructose was found to be higher than that of glucose. The ratio fructose:glucose cannot therefore be used as a criterion for purity in orange and grapefruit juices but may serve as a useful tool to detect addition of sucrose to other fruit juices.