In seeking to raise tax income, local governments often appeal to changes in the types and rates of taxes. However, at the same time, tax exemptions are use as a stimulus to growth and competitiveness, and these reduce government income and increase pressure on other taxpayers. This study examines the effect of changes in tax rates on tax income in the District of Cartagena, Colombia. We calculate tax income-elasticity to changes in the Mean Tax Rate (MTR) relationship known as the Laffer Curve. We find that tax income is inelastic to changes in MTR This result suggests that policies to raise tax income through a general hike in tax rates are not effective.