The fact that property tax values are lowerthan market values leads to losses in propertytax. Inaddition, reales tate tax value is used in taxation of realestatecapita lin come, inheritanceand transfer tax, title deeds and determination of taxpayer ssubject tosimple procedure. The fact that the value of property tax does not reflect market values also leads to a loss in value added tax and land registry feerevenues in building sales. A total of 100 realestate samples from Gebze District of Kocaeli province were take nandtheproperty tax values and market valueswerecompared. Market valueshaveincreased 2.55 times more than the property tax values of buildings. The market value of the and was 9,70 times higherth ant herealestate tax values. It was determined that the property tax values of the propertie ssubject to review were lowerthantheir market value, resulting in taxlosses as a result.