The question was investigated, whether chelators alone can solubilize different lignites. For that purpose the influence of eight chelators were tested on different pretreated or natural lignites. The effects of the pretreatment and of the concentration of chelators were studied. The results show that different chelators have different influence on different lignites. Oxidative pretreatment enhances the solubilization. At low chelator concentrations only leonardite is solubilized to remarkable degree. Ammonium oxalate is one of the most effective agents. The results confirm that chelators alone are not able to solubilize lignites with a very low ash or oxygen content.