Using a flue-cured tobacco variety, BU 109, effect of growth regulators(Fatty Alcohol and C-MH) on the change of invertase activity and sugar metabolites were investigated. Invertase activity in untreated leaf tissue was decreased along with maturation of leaf, However, a momentary increase of the activity was observed in leaves by the dual treatment of fatty alcohol and C-MH regardless of leaf position while sole C-MH treatment resulted in activity increase by 14 days after the treatment. Similar tendency was observed in stalk. Sugar content in leaf was increased immediately after the treatment but no significant increase at large resulted until 14 days after treatment. After harvest, reducing sugar was increased by the growth regulators. Nevertheless, in case of dual treatment, the total sugar content was not different with that of untreated control. R/T ratio was gradually increased after topping stage and reached maximum at 14 days after treatment of growth regulators. It decreased a little after harvest but the RR ratio was relatively higher due to increase of reducing sugar resulted by the treatment of the chemicals. Upon treatment of growth regulators, reducing sugar content was increased in lugs and leaves compared to untreated control and the content of sugar metabolites was increased by the use of the chemicals either at lower or higher than recommended dose. Key words : MH, FA, invertase activity, total sugar, reducing sugar