The combustion characteristics of cellulose insulation treated with several metal complexes such as Aluminium hydroxide, Cupric sulfate pentahydrate, Magnesium sulfate heptahydrate, Manganese chloride tetrahydrate and Trisodium phosphate dodecahydrate are studied to evaluate the effectiveness as a potential flame retardant for cellulosic materials. In this study, we found that LOI values of cellulosic materials treated with the metal complexes are generally increased with the increase of their content. At high concentration, CS(24%) and SP(24%) show high LOI values, suggesting resistance to flame spread. The materials examined in this study were found to be relatively more resistance to smouldering and flaming combustion in comparision with untreated cellulosic material. The flammability behavior of the materials exhibits combustion process as follows : LOI→smouldering region→smouldering-flaming spread region→flame spread region.