The Model for Interdisciplinary Research on Climate (MIROC5) is a new version of the coupled general circulation model developed by the Japanese research community. It was used to perform a century-long control experiment with standard resolution. The model's climatological mean state and variability were compared with observations and those from a previous version (MIROC3.2) with different resolutions. MIROC5 showed improvements in precipitation, zonal mean atmospheric fields, equatorial ocean subsurface fields, and the simulation of El Niño–Southern Oscillation (ENSO). The difference between MIROC5 and the previous model is larger than that between the two MIROC3.2 versions, indicating that updating parameterization schemes has a greater effect on the model climate than increasing resolution. The mean cloud property in MIROC5 shows good agreement with satellite measurements. MIROC5 reveals an equilibrium climate sensitivity of 2.6 K, which is lower than that in MIROC3.2 by 1 K. This is likely due to the negative feedback of low clouds to increasing CO₂ concentration, which is opposite to that in MIROC3.2. MIROC5 has a more accurate representation of cloud and cloud-radiative feedback, with a prognostic LSC scheme and a bulk microphysical scheme. The model also includes an updated turbulence scheme that reduces some common deficiencies of the Mellor–Yamada scheme. The aerosol module in MIROC5 predicts the mass mixing ratios of main tropospheric aerosols and their precursor gases. The ocean component of MIROC5 uses COCO version 4.5, which has a generalized curvilinear horizontal coordinate system and improved vertical resolution. The sea ice component in MIROC5 predicts sea ice concentration, ice thickness, snow thickness, and energy of ice melting for multiple categories. The land component of MIROC5 uses an updated version of the land surface model, MATSIRO, which predicts temperature and water in six soil layers down to a 14-m depth. The control experiment for MIROC5 was conducted with boundary conditions based on historical changes in total solar irradiance and volcanic aerosol optical depth. The model's climatological mean states and variability were validated against observational datasets, showing improvements in several aspects. The model's mean states and variability were compared with observations, revealing that MIROC5 has a more realistic representation of the global mean radiative budgets, temperature, and hydrological quantities. The model's precipitation pattern was compared with CMAP data, showing a sharp contrast between heavy precipitation regions. The model's zonal wind stress and ocean subsurface states were validated, showing that MIROC5 has a more accurate representation of the Pacific trade winds and the central equatorial Pacific SST. The model's subsurface temperature climatology was compared with observations, showing that MIROC5 has a more accurate representation of the warm pool and the EUC. The model's Arctic and Antarctic sea ice concentration was compared withThe Model for Interdisciplinary Research on Climate (MIROC5) is a new version of the coupled general circulation model developed by the Japanese research community. It was used to perform a century-long control experiment with standard resolution. The model's climatological mean state and variability were compared with observations and those from a previous version (MIROC3.2) with different resolutions. MIROC5 showed improvements in precipitation, zonal mean atmospheric fields, equatorial ocean subsurface fields, and the simulation of El Niño–Southern Oscillation (ENSO). The difference between MIROC5 and the previous model is larger than that between the two MIROC3.2 versions, indicating that updating parameterization schemes has a greater effect on the model climate than increasing resolution. The mean cloud property in MIROC5 shows good agreement with satellite measurements. MIROC5 reveals an equilibrium climate sensitivity of 2.6 K, which is lower than that in MIROC3.2 by 1 K. This is likely due to the negative feedback of low clouds to increasing CO₂ concentration, which is opposite to that in MIROC3.2. MIROC5 has a more accurate representation of cloud and cloud-radiative feedback, with a prognostic LSC scheme and a bulk microphysical scheme. The model also includes an updated turbulence scheme that reduces some common deficiencies of the Mellor–Yamada scheme. The aerosol module in MIROC5 predicts the mass mixing ratios of main tropospheric aerosols and their precursor gases. The ocean component of MIROC5 uses COCO version 4.5, which has a generalized curvilinear horizontal coordinate system and improved vertical resolution. The sea ice component in MIROC5 predicts sea ice concentration, ice thickness, snow thickness, and energy of ice melting for multiple categories. The land component of MIROC5 uses an updated version of the land surface model, MATSIRO, which predicts temperature and water in six soil layers down to a 14-m depth. The control experiment for MIROC5 was conducted with boundary conditions based on historical changes in total solar irradiance and volcanic aerosol optical depth. The model's climatological mean states and variability were validated against observational datasets, showing improvements in several aspects. The model's mean states and variability were compared with observations, revealing that MIROC5 has a more realistic representation of the global mean radiative budgets, temperature, and hydrological quantities. The model's precipitation pattern was compared with CMAP data, showing a sharp contrast between heavy precipitation regions. The model's zonal wind stress and ocean subsurface states were validated, showing that MIROC5 has a more accurate representation of the Pacific trade winds and the central equatorial Pacific SST. The model's subsurface temperature climatology was compared with observations, showing that MIROC5 has a more accurate representation of the warm pool and the EUC. The model's Arctic and Antarctic sea ice concentration was compared with