A rock drilling rig and to a method for transmission thereof is provided. The rock drilling rig includes a carriage that is movable by drive equipment in a mine. The rock drilling rig includes a hydraulic drilling system for which pressure energy is generated by a hydraulic pump. The rock drilling rig is electrically driven and includes an electric motor that is connected to drive both the drive equipment and the hydraulic drilling system. The mechanical drive transmission included in the drive equipment and the hydraulic pump of the hydraulic drilling system may be connected and disconnected independently of one another by means of clutches.