Many countries tax voluntary pension savings using the so-called EET model, based on tax-deductible savings and taxable withdrawals. In Finland the tax reform of 2005 changed the tax rate schedule from progressive to proportional, while the basic structure of the EET model was retained. This paper is an empirical study of changes in savers? behaviour as a result of the reform using individual level data. The econometric estimations indicate that the reform altered pension saving behaviour by reducing the labour income and age effects on saving contributions in a statistically significant way. Also, the reform reduced the number of pension savers among high income-earners.