Taxable income in Spain changes in response to tax rate changes. From 1999 to 2014, the elasticity of taxable income was between 0.45 and 0.64. Self-employed individuals are more sensitive to tax rate changes than employees. Business income is more affected than labor and capital income. The elasticity of broad income is smaller, between 0.10 and 0.24. Some tax deductions, like private pension contributions, have an elasticity exceeding one. These findings are consistent across different methods and sample restrictions, and are not influenced by mean reversion or income trends.