Abstract: Modification of the method for determination of total mercury in coal by oxygen flask combustion was proposed. Coal sample was burned in a crucible heated electrically by nichrome wire in an oxygen flask. Mercury vapour evolved was absorbed in a solution of potassium permanganate in sulfuric acid (1+9). The divalent mercury ion in the solution after reduction of permanganate with hydroxylamine hydrochloride solution was ready for determination of its content by FI-HG-AAS (cold vapour). Linearity between the absorbance and concentration of mercury (expressed as μg·L-1) was obtained with a correlation coefficient of 0.999 7. In analyzing 10 portions of the same sample by the method proposed,average value of mercury content found was 0.558 μg·L-1 with RSD (n=10) of 4.8%. Test for recovery was made by addition of standard mercury solutions of 3 different concentrations to a same coal sample,and results obtained were in the range of 91.4%-97.3%. It was proved that this method is feasible for the routine analysis of large number of samples.