The aim of this study was to investigate the earthquake hazard of the East Anatolian Fault Zone by determining the a and b parameters in a Gutenberg-Richter magnitude-frequency relationship. For this purpose, the East Anatolian Fault Zone is divided into five different source zones based on their tectonic and seismotectonic regimes. We calculated the b value, which is the slope of the frequency-magnitude Gutenberg-Richter relationship, from the maximum likelihood method (ML). Also, we estimated the mean return periods, the most probable maximum magnitude in the time period of t years and the probability for an earthquake occurrence for an earthquake magnitude a parts per thousand yenM during a time span of t years. We then produced a and b value maps using the ML. We obtained the lowest b value in Region 1 covered KarlA +/- ova triple junction. This conclusion is strongly supported from the probability value, which shows the largest value (90 %) for an earthquake with magnitude greater than or equal to 6.0. The mean return period for such a magnitude is the lowest in this region (43 years). The most probable magnitude in the next 100 years was calculated, and we determined the highest value around KarlA +/- ova triple junction. According to these parameters, Region 1 covered the KarlA +/- ova triple junction and is the most dangerous area around the East Anatolian Fault Zone.