We present the first direct observations of convection electric fields in the earth's magnetotail. The electric fields have been measured from lunar orbit by detection of the E¿B/B2 drift displacement of low-energy electrons at the limb of the moon. We find the following. (1) Electric fields range in magnitude from ≲0.02 mV/m, the limit of sensitivity of the method, up to 2 mV/m. The typical value is 0.15 mV/m, and the corresponding convection velocity is 15 km/s. (2) The sense of the electric field is almost always dawn to dusk. (3) The electric field is often variable on a time scale of hours and sometimes minutes. (4) The observations indicate that the electric field is not uniform across the magnetotail. If it is assumed that the typical measured electric field value represents an average over the inhomogeneous, the potential drop across the entire tail is ~40 kV.