The present study was conducted at the Bureau of Mines to explore the effect of a variety of molten nitrate salts on the thermal decomposition of one oil shale sample from the Green River Formation. Thermal analysis, coupled with effluent gas analysis, was used for all the tests in which the samples were heated at a constant heating rate. Weight losses of heated oil shale in the presence of nitrates were found to be higher than similar losses in the absence of nitrates. Ammonium nitrate degraded the oil shale at a lower temperature than that at which oil shale started to decompose when heated by itself, or in the presence of sodium nitrate or potassium nitrate. From scanning electron microscopy of the heated oil shale samples, it appears that ammonium nitrate attacked both the inorganic and the organic portions of the shale. These results indicate that a more detailed investigation of the effects of ammonium nitrate, and perhaps other nitrates, on fuel recovery from oil shale will be a worthwhile undertaking.