Abstract: An endoscope deflection control is described whereby enhanced one-hand control of the tip of a polydirectionally deflectable endoscope is obtained. The deflection control is mounted external to the head of the endoscope in such manner that convenient single-hand manipulation of deflection control wheels mounted on the head provides tip deflection in either a freewheeling deflection mode or an incremental mode characterized by discrete stable incremental tip deflections. Single-hand operation of the endoscope deflection control is obtained by locating incremental deflection position elements in a compact structure which is wholly or partly external to the head while the control wheels remain within manipulatable reach of the single hand's fingers.