According to GFS manual of IMF, taxes are defined as compulsory, unrequited, nonrepayable contributions exacted by a government for public purposes. Also included in taxes are any collections of fees and charges out of all proportion to the cost or distribution of government service provided to the payer. This paper has explored some of 'compulsory, unrequited, nonrepayable contributions' are not regarded as taxes in Korea because their titles are not tax. Most of those called as 'Quasi-Tax' in Korea should be classified as tax according to the tax definition and the revenue classifications of GFS manual.