A safety cap for use with a needle, the cap including an opening in the cap adapted to receive a needle therein, a releasable lock mechanism disposed within the opening, and a permanent lock mechanism disposed within the opening. The safety cap may be provided on a needle, the releasable locking mechanism being actuated to release the needle from the cap. After use, the needle may be reinserted into the safety cap and permanently locked therein by the permanent locking mechanism, thereby providing for safe disposal of the used needle.