For the last years, several power cycles which consider supercritical CO2 as working fluid have been analyzed in detail. Due to their potential thermodynamic efficiency, their compactness and their expected operational flexibility if compared with conventional Rankine cycles, they are attracting the RD Community interests worldwide. The paper deals with the layout arrangement and machinery design of a 15 MW power group for a supercritical recompressed cycle. Starting from a conventional twin-shaft layout, the final one was arranged on three shafts at different speed. Moreover, all the components have been iteratively designed using preliminary 1-D and 2-D models and, then, they have been modelled in detail by means of the commercial Ansys-CFX software. Finally, a power group with a nominal output power of 13 MW and an overall efficiency of about 57% (taking all kind of losses into account) was achieved.