The present invention relates to a small diameter endoscope in which a handle is removably attached to a probe. The probe includes a fiber optic illumination channel that is concentric about an imaging channel. The handle includes an imaging device that detects light from the imaging channel and a sterile barrier that can be extended over the handle for use. Relay optics couples the small diameter imaging channel to the imaging device in the handle. The probe has a mounting hub that connects the probe to the handle and also serves to optically couple the fiber optic illumination channel to a light source.