A fiber optic probe is disclosed for delivering laser radiation from a medical laser system to a treatment site. The probe includes a handpiece having an axial channel. The axial channel includes an intermediate mating region of reduced diameter. A tip piece having a fiber located therein is mounted on the front end of the handpiece. The input end of the fiber is mounted in a ferrule which is received in the reduced diameter mating region of the handpiece. A tail piece which includes an optical fiber is mounted at the rear end of the handpiece. The delivery end of the fiber in the tail piece is mounted in a ferrule and is also received in the mating region of the handpiece. The two ferrules are spring biased together to maximize coupling efficiency. The mating region is spaced from the front end of the handpiece so that the force on the mating region, caused by the torque imparted to the tip piece during use, is less than it would be if the mating region were located at the front end whereby the coupling efficiency is maintained. The handpiece is designed to be reused after sterilization in an autoclave.