A single use safety syringe (10) has a barrel (12) having a leading end (14) and a trailing end (16). A needle 18 is sealably, but removably, attached to an opening in the leading end. A plunger (20) is slidably received through an opening in the trailing end. Upon completion of an injection, the plunger (20) engages the needle (18) and the needle can then be manually re-tracted into the barrel (12). A locking tab assembly (42, 44, 50, 52) is securely connected to a main body of the barrel (12) and forms the opening in the trailing end (16). The locking tab assembly includes two locking fingers (78, 80). The plunger (20) has a locking plate (41) which includes two locking ports (86, 88). The locking fingers (78, 80) and locking ports (86, 88) form a needle locking assembly. The locking fingers (78, 80) are adapted to engage by a hooked fit the locking ports (86, 88) when the needle (18) is fully retracted after use to prevent any subsequent movement of the plunger (20) with the engaged needle towards the leading end. Upon such engagement, a holding plate (36) secured to the plunger (20) below the locking plate (41) butts up against the bottom of holding rings (82, 84) of the locking tab assembly to prevent any subsequent movement of the plunger with the engaged needle towards the trailing end.