Abstract: To produce hollow articles of a thermoplastic by extrusion blowing a parison is transferred from the extruder die into the blow mold by means of a gripper device comprising two gripper arms which work hand-over-hand, alternatively grip the parison as it issues from the die and draw it at an adjustable take-off speed, which is greater than the speed of extrusion, into a blow mold waiting under the die, and the blow mold, after the gripper arm has passed the lower edge of the mold, closes about the parison still hanging from the die, the second gripper arm grips the parison just above the blow mold before the parison is severed between the upper edge of the mold and the gripper arm, the filled blow mold makes room for the next blow mold, the parison inserted in the mold is inflated in a manner which is in itself known to form the hollow body, the latter is released from the mold, and the entire sequence is repeated as a continuous set of cycles.