The cost estimate for bill is a measure to estimate the fiscal burden in case the proposed bill becomes an act. The purpose of this paper is to analyze whether the cost estimation had a substantial effect on the revision of the budget-related provisions in the bills to be considered in the National Assembly of Korea. After analyzing the budget-related bills that went to acts in the 17th National Assembly(year 2004~2008), the paper concluded that (1) the bill cost estimation had a significant effect on the bills sponsored by the lawmakers, (2) while it came to little effect on the bills introduced by the executive branch. This paper suggests that the current rule of cost estimation which requires cost estimate in the introducing stage of bill may be changed into attaching a cost estimate result to the final version of bill that is ordered to be reported to the floor.