Olive (Olea europaea L.) has great genetic variation in Turkey as important crop due to its economic value. There are many cultivars, types and landraces with various morphological characters in different ecological conditions of Turkey, having good potential for productivity, oil quality and table olive characters. The northwestern region of Turkey with cool subtropical climate has most suitable ecological conditions for highest quality olives and olive oils. This research was carried out to compare some biochemical and pomological characteristics of six local olive cultivars including 'Ayvalik', 'Domat','Gemlik', 'Memecik', 'Samanli' and 'Uslu', which are widely grown in Turkey. Cultivars were collected in intervals of about 10 days from September 15 to December 22 in 2014. In this research fruit width (mm), fruit length (mm), fruit weight (g of 100 fruits), moisture content (%), pulp ratio (%), maturity index (MI), total chlorophyll content (mu g mL(-1)) and total carotenoid content (mu g mL(-1)) were determined. As a result of study, concentrations of total chlorophyll decreased although concentration of carotenoids increased when skin color of fruit is turning red, purple or black on more than a half of the surface (Maturity Index>3 and MI=4). Also fruit size enlarged with the increase of maturity.