A retractable needle assembly is disclosed. The needle assembly consists of a syringe body, having a needle assembly on one end and a plunger assembly on the opposing end. The needle assembly, which enables and disables fluid communication between the needle and fluid reservoir, comprises a generally cylindrical body sealably disposed within the lower interior of the syringe body. The cylindrical body is rotatable, facilitated by a knurled ring, within the syringe body. Rotation of the cylindrical body causes either enablement or disablement of the needle assembly. Tabs, located on the syringe body are received within notches, separated by one-way and two-way ramps, located on the cylindrical body, such that the ramps facilitate either temporary or permanent disablement of the device. Plunger lock means are also disclosed.