In this study, the distribution of and principal threats to Caucasian black grouse Tetrao mlokosiewiczi in the Eastern Karadeniz Mountains, Turkey, are examined. A total of 36 observation sites was selected in such a way as to represent the whole range of the study area. Observations were carried out from May 1993 to July 2002. The results show that the Caucasian black grouse is present in the Eastern Karadeniz Mountain from Salarut Yayla in the Ziyaret Mountains in the west to Cukunet Yayla in the Karcal Mountains in the east. Principal threats to the species were determined to be habitat degradation, habitat loss and fragmentation (e.g. intensive forestry practices, wood smuggling, road construction, mountain summer house (yayla) construction, fuel-wood utilization of shrubs, intensive and extensive grazing and hay production), small population size, poaching, egg collection, fox predation and outdoor activities.