Between 1988 and 1993, the Belgian personal income tax system and the indirect tax system were reformed to a considerable extent. We use microsimulation models to investigate the impact of the reform on the liability progression and the redistributive effect of the combined tax system. The redistributive effect of personal income taxes decreased, notwithstanding an increase in liability progression. For indirect taxes, both the liability regressivity and the reverse redistributive effect have been enhanced. We use recently developed statistical tests to gauge the significance of the observed changes.