This paper reports a transient strong diamagnetic event observed with the ISEE-1 and -2 spacecraft in the near-Earth magnetotail. Magnetic signatures associated with the event resemble those of flux rope events found in the distant magnetotail. The present event should be distinguished from those in several previous reports based on the following points: (1) The event is observed in the near-Earth tail (X~-17 RE), not in the distant tail. (2) The tail field changes from a stressed configuration to a more dipolar one in the course of the event, and the plasma data suggest that the heating and the resultant expansion of the plasma take place simultaneously. (3) The minimum of the magnetic field strength BT is ~1 nT; such a strong depression is rarely observed in the near-Earth tail. (4) An earthward plasma jet (300 to 500 km/s) continues for about 3 min, including a period of very weak magnetic field; the duration of the jet is exceptionally long compared to previously reported high-speed flows in the plasma sheet. These magnetic field and plasma signatures are discussed in terms of two models: an earthward-moving plasma bulge and a tail-aligned flux rope. ¿ American Geophysical Union 1992