We report on a diode end-pumped composite core-doped ceramic Nd:YAG laser. The ceramic Nd:YAG rod consists of a centrally doped region of 1.5 mm in diameter in a 3 mm rod. An output power of 144 W was achieved with an absorbed pump power of 226 W corresponding to an opt.-opt. efficiency of 64 \% by longitudinal pumping with fiber-coupled laser diodes.