Abstract: Miocene units at the north Beypazarı (Ankara) are represented by conglomerate, agglomerate, sandstone,siltstone, clay stone, coal, bituminous shale, limestone and tuffs. Exposures of bituminous horizons just above coal areobsewed in extensive areas in the region. Total organic carbon content obtained from different outcrops of thisbituminous horizon varies from % 0.37 to % 7.07 organic matter, mainly dominated by algal origin, is of type 1 and 2kerogen. Vitrinite reflection measurements vary between % 0.27 - % 0.56 and Tmax values obtained from Rock -Eval pyrolysis are in the range of 407 - 437°C. These data point out that organic matter is immature. Biomarkercharacteristics also verify this results. The Ts/Tm ratio is 1.5 and show immaturity of organic matter. According tothe Pr/n-Cjy and Ph/n-Cjs, Miocene units were generated in reducing environments and their source is shale.