Plastic hypodermic needles are a potential solution to the problem of disease spread through needle reuse. Plastics could be used to potentially reduce needle reuse as they are easier to destroy than steel. A key issue in their acceptance is the force required to penetrate a patient; a smaller force is associated with less pain. The effect that needle parameters have on the penetration force is studied in an effort to better understand how to reduce penetration forces and increase the success of penetrations for plastic needles. These parameters - geometry, tip radius, diameter, material, and lubricant - are studied through penetration, buckling, and coefficient of friction testing. The tests are conducted on steel needles, which serve as a control group, as well as two varieties of plastic needles. The outcome is a quantitative understanding of the effect that the various parameters have on penetration force, which is used to inform plastic needle design.