In this study, the gamma dose rates in outdoor air at seventy-seven points around Bolu province were meausured using a counter (Eberline, ESP-2). Radiological hazards were evaluated by estimating the excess lifetime cancer risks caused by external exposure. The gamma dose rates measured varied from 11 to 68 nGyh-1with an average value of 22 nGy h(-1). The avarege value of the corresponding outdoor annual effective dose and the excess lifetime cancer risk was found as 27.23 mu Sv and 0.95x10(-4), respectively. These values could be compared to other studies which existed in Turkey and also in the world.