An improved process and apparatus for production of synthetic multifilamentary yarns having uniform quality. The method comprises extruding a molten synthetic polymer downwardly through a spinneret, advancing the extruded filaments downwardly through a substantially stationary column of heated air, and subsequently advancing the filaments downwardly through a quenching zone wherein they are in contact with cooling air introduced into the path of the filaments under controlled conditions of air velocity and direction of flow. The apparatus for carrying out the process comprises an extrusion spinneret for extruding a number of filaments directly into a heated sleeve having walls that are imperforate, said heated sleeve leading to a quenching chamber having opposite, essentially vertical inlet and outlet panels for allowing cooling air to pass through the chamber, and means for regulating the stream of cooling air whereby both the velocity of the air stream going through the quenching chamber and its general direction as it contacts the descending filaments may be regulated.