Among anthropogenic emissions of atmospheric mercury, 25% originate from coal burning. For Brazil, the estimate is 1.0 t Hg/year. Data about Hg concentrations in coal are scarce. A method has been optimized based on analysis of solid to determinate Hg in coal samples based on thermal decomposition and detection by AAS. The Brazilian coal samples analyzed with the validated method presented concentrations in the range 0.132 to 0.293 mg/kg.