Abstract: A hypodermic safety syringe assembly (10) includes a cylindrical barrel (12) having a front end defining a first aperature (14) and a rear end defining a second aperature (16), a closure member (32) shaped to engage the barrel (12) at or adjacent the front end thereof to seal the first aperature (14), and a piston assembly (18) reciprocally movable within the barrel (12) and includes a retractor (20) terminating in a piston formation (24) engageable with the closure member (32) to disengage the closure member from the front end of the barrel so that a hypodermic needle (40) attached thereto can be withdrawn into the barrel (12) after use, wherein the closure member (32) includes a barrel engaging formation (44,48) releasably engageable within a closure member engaging formation (64) at the front end of the barrel (12), and a piston coupling formation (50,54) for engaging a closure member coupling formation (68,69) on the piston (24), with inter-engagement of the piston and closure member coupling formations (