The miniaturization and improving performance of electronic devices has lead to increasing power densities in electronic systems. Consequently, the thermal environment has become a main issue in their performance and reliability. The use of flat miniature heat pipes has been investigated for transferring the heat over distances or to spread it over a larger surface area to avoid hot spots on the device. The interest of silicon etching techniques for heat pipe manufacturing is that such heat pipes can be very compact, very light and have better heat transfer capacities than metallic heat pipes. In this paper the structure of a flat radial structure silicon heat pipe is presented. A one dimensional two-phase flow model has been developed in order to optimize the performances of the radial grooved silicon heat pipe. Then an experimental study investigates the thermal performance of a realized prototype. The thermal transfer capacities achieved are in the range 50-70 W depending on the working temperature