A methodology was used to evaluate Low Temperature Ash (LTA) and High Temperature Ash (HTA) through Mossbauer Spectroscopy (MS). Siderite was the only Mossbauer Spectral presenting a good correlation between the spectral area and the ash content obtained by LTA and HTA, The calibration curves obtained for HTA and LTA gave a correlation coefficient of 0.968 and 0.988, respectively. The LTA results present the best correlation, given that this process does not change the original mineral phases. This methodology was the advantageous for easily obtaining coal ash content, through curve ash content vs. MS area, without carrying out ashing processes. (C) 2005 Elsevier Ltd. All rights reserved.