Climate change has recently become one of the most important issue discussed by scientists around the world. The purpose of this study is to investigate the possible effects of climate change on temperature and precipitation variables, which are among the most major climate variables in terms of their environmental and economic impact for the rainiest region of Turkey. General circulation models (GCMs) under different emission scenarios are widely used in determining possible changes in the climate system. However, the coarse resolutions of these models are unsuitable for the climate impact/adaptation studies at basin scale. In this paper, the future monthly mean temperature and precipitation for 12 station in the Eastern Black Sea Basin, Turkey were projected for three periods 2030s (2021–2050), 2060s (2051–2080), and 2090s (2081–2100) from the three GCMs, namely CNRM-CM5.1, HadGEM2-ES, and MPI-ESM-MR, under RCP4.5 (optimistic) and RCP8.5 (pessimistic) scenarios using the multivariate adaptive regression splines (MARS) statistical downscaling method. The statistical downscaling models were set up between the 12 potential predictor, obtained from ERA-Interim reanalysis data set, and the local station data. For evaluating and the performance of the downscaling models four performance statistics namely root means square error, scatter index, mean absolute error, and the Nash Sutcliffe coefficient of efficiency, were used. Thereafter, the calibrated and validated models were applied to downscale future scenarios of the GCMs. The results obtained from the study proved that the downscale temperature and precipitation values correlated well with the observation values for the training (1981–2004) and test (2005–2010) periods. An average increase of 2.5 and 2.0°C is foreseen according to the optimistic scenario and an average increase of 3.5 and 3.0°C is foreseen according to the pessimistic scenario in the southern and northern parts of the basin, respectively. As to precipitation, a decrease is expected in the southern part of the basin but a significant increase is expected especially in spring at the stations located in the western and coastal parts of the basin.