Data from the SAMPEX spacecraft has shown the presence near L=1.9 of the remnants of the ultrarelativistic electrons (above 15 MeV) injected into the magnetosphere on 24 March 1991. The decay of the electrons has been tracked since July 1992. The electron e-folding lifetime is in the range of six to twelve months, and the location in L of the peak intensity moved inward by ~0.05 units in one year. The inferred electron lifetime is similar to that of ~0.5 MeV electrons, which is in agreement with extrapolation to higher energies of the theoretical estimates of Lyons and Thorne (1972). ¿ American Geophysical Union 1994