Safety cap for medical needles

To protect against the health and safety risks that accompany accidental post-use needle sticks, a medical needle assembly equipped with a safety cap is described. The disclosed medical needle assembly generally includes a needle hub, a needle having a magnetized distal end, and a removable safety cap attached to and extending radially from the needle hub. In another embodiment, the removable safety cap is attached to a sheath that covers the needle. The safety cap includes a magnet and a retainer disposed between the first and second ends of the cap. The retainer is configured to prevent withdrawal of the needle once the needle perforates the retainer and the safety cap encloses the distal end of the needle.