A novel giant magnetoresistance memory effect has been observed in epitaxial Nd0.7Sr0.3MnOzthin films which have previously been found to exhibit a linear increase in conductivity on first application of magnetic fieldB. The resistivity of the films depends not only on the instantaneous applied field but also on the magnetic history of the sample. AtTwell below the temperatureTp, where the zero‐field resistivity has a peak, the film enters a high‐conductivity state (upon application of a magnetic field) which persists even whenBis reduced to zero. The original ‘‘zero’’ field state is not recovered until the sample is warmed toT∼Tp. Surprisingly, the dc magnetization exhibits only a weak irreversibility while the magnetoconductivity is markedly hysteretic. A possible explanation is proposed. ©1995 American Institute of Physics.