A bone cement mixing and delivery system including a mixer and a delivery device. The mixer includes a paddle for mixing the components and a piston that pushes the mixed cement into the attached delivery device. The delivery device includes a tube into which the bone cement is forced from the mixer, and a plunger that forces the cement out of the tube during the medical procedure. The tube includes an entry port through which cement is introduced into the tube from the mixer. A one-way valve attached to the tube allows the cement to flow from the mixer through the entry port. After the cement is loaded in the tube, the delivery device is removed from the mixer. The valve blocks flow out of the entry port when the plunger is depressed.