Abstract: A bent-axis compressor, particularly suitable for compressing refrigerant vapors, in which a plurality of spaced bent-axis double acting reciprocating pistons are operatively joined to two separate rotatable cylinder blocks driven by a power transmission around a statonary bent axis central shaft; the improved arrangement in which the central shaft and the pistons are hollow, a vapor inlet port is located at the center of each piston at the plane joining the two halves of the piston and on the side having an exterior obtuse included angle between the two halves, valved passageways leading from inside the piston to each head of the respective cylinder, and from the cylinder head to the interior of the central shaft for exit therefrom as a compressed vapor.