Olive is the most widespread fruit plant in the Mediterranean whose fruit is one of the oldest types of food, which was historically used as medicine as well. The olive attack about twenty kinds of insects which make a significant economic damage and therefore need to be monitored and combated. Economically the most significant pest of olive is a olive fruit fly (Bactrocera oleae Gmel.) which affects the quantity and quality of olive oil. The object of this research was to determine the dynamics of olive fruit fly occurrence using yellow sticky insect traps, and visually examination of the fruit determine the intensity of the attacks. During 2014th, the research was carried out on the Oblica cultivar in two olive orchards on the island of Brač. In the first orchard, the olive fruit fly control was not conducted, while in the second orchard the olive fruit fly control was conducted twice, using the treatment with dimethoate. Extremely favorable climatic conditions low temperatures and high relative humidity have enabled in both orchards the development of three generations of the olive fruit fly. The first generation was fully developed by the end of July, the second by the end of August, and the third by the end of September 2014. The highest infestation caused the attack of the third generation. The height of population and the damage of the olives in untreated orchad was higher than in the treated olive orchard. Because of the large fruits, the Oblica cultivar is very attractive for the olive fruit fly and with favorable climatic conditions at 2014th, at most of olive orchards on the island Brač were missing harvest.