gamma-Fe3O4 doped polyirnide films with different weight percentages (1, 5, and 10 wt % of Fe3O4) have been prepared and the effect of nonmagnetic gamma-Fe3O4 content on the structural and magnetic properties has been studied. X-ray diffraction (XRD) studies revealed that the nanopowders obtained are magnetite. The calculated grain sizes from XRD data have been verified using scanning electron microscopy (SEM). SEM micrographs show that the powders consist of nanometer-sized grains. Magnetic hysteresis loops were measured at room temperature with a maximum applied magnetic field. As the gamma-Fe3O4 content increases, the measured magnetic hysteresis curves become more and more narrow and the saturation magnetization and remanent Magnetization both decreased. The prepared nanocomposites were identified in terms of their structure, morphology, and magnetic and thermal properties. These studies showed that the particles seem to be dispersed randomly, although the particles do appear to form aggregates at increasing particle loadings.