Abstract: A drive mechanism for an infusion pump linearly moves a syringe plunger within a syringe barrel supported by the pump and includes: (i) a motor; (ii) a lead screw rotatably connected to the motor; (iii) a slide assembly having a threaded member supported thereon, the threaded member being associated with the lead screw; (iv) an arm having one end connected to the slide assembly and one end adapted to be engaged with the syringe plunger, and (v) the threaded member being rotatably biased in engagement with the lead screw, wherein upon rotation of the lead screw by the motor, the slide assembly linearly moves the arm wherein the arm is adapted to move the syringe plunger within the syringe barrel.