A safety scalpel incorporating a handle similar in thickness, length, weight, balance, shape and feel to the conventional metal handle preferred by most surgeons, and a disposable cartridge assembly that is easily mounted and released from the scalpel handle. The handle comprises a first end and a second end. The cartridge assembly comprises a blade guard/shield that can be slideably mounted onto the second end of the handle, a blade holder/slider that can be disposed within the blade guard, and a blade that can be attached to the blade holder. The safety scalpel incorporates a locking system that prevents the cartridge assembly from sliding off or wobbling on the handle during use.