A gas-turbine blade of solid construction and having cooling passages is specified, which cooling passages run in its interior and through which the cooling medium flows essentially from the blade root through the gas-turbine blade (100), these cooling passages (20) having a relatively small cross section in relation to the blade thickness and being arranged so as to run close to the lateral surface (100.1) of the gas-turbine blade (100), and the cooling-medium feed and discharge being effected in the base (60) of the gas-turbine blade (100).