Abstract: A convenient low-cost system is disclosed for digitally displaying instrument locations during a stereotaxic procedure on an animal such as a rat or mouse. This system, which can be retrofitted onto most types of existing stereotaxic manipulators, uses three optical or capacitance scaling devices, mounted orthogonally. An electronic reader head interacts with each scaling device, to measure the position and travel of the manipulator along the medial-lateral (X), anterior-posterior (Y), and dorsal-ventral (Z) axes. Each reader head sends electronic signals to a small display box that can be placed or mounted in any convenient location, or to a computer with a monitor, and all three coordinates are displayed continuously. This system provides a simple zeroing function, which can set all values to zero when an instrument tip reaches a fixed location such as the bregma point on a skull.