Some organic acids and sugars in two blueberry species from north-east Anatolia, Turkey, were studied. The fruits of the blueberry species (Vaccinium arctostaphylos L. and V. myrtillus L.) were collected at three stages of maturity (immature, mid ripe, and ripe), and the organic acids and sugars were studied by gas liquid chromatography (GLC) and verified by gas liquid chromatography-mass spectrometry (GLC-MS). The soluble sugars fructose, glucose, and sucrose, and the sugar alcohol inositol were identified and quantified. Fructose and glucose represented the major sugars in the fruits. Quinic and citric acids were found to be the major organic acids in both blueberry species. The levels of these acids were significantly different (P = 0.05) at all three stages of fruit maturation. The level of malic acid increased gradually in both species, whereas the levels of citric and quinic acids decreased rapidly. The total acid level in the fruits of the two species was also significantly different. The results of this study can be used to compare the two species with other Vaccinium species.