A syringe including a barrel (14), a retractable needle (12) and a plunger rod assembly (22) including inner (30) and outer (24) members with a stopper (46) for expelling fluids from the syringe is disclosed. An activation member (40, 44) associated with the plunger rod permits relative movement of the inner and outer members when activated. The stopper is configured to compress a sufficient amount when advanced distally in the barrel to cause the activation element to engage and cause retraction of the needle within the syringe.