We estimate the effects of four unit-based pricing systems on waste collected in Dutch municipalities. Unit-based pricing is shown to be effective in reducing unsorted and compostable waste and in stimulating recyclable waste. If the estimations are corrected for differences in environmental activism between municipalities the effects are still large but significantly lower. The bag- and weight-based systems perform equally and far better compared with the frequency- and volume-based systems. This is interesting, as administrative costs are significantly lower for the bag-based system. Finally, unit-based pricing has no effect on the amounts of waste collected in surrounding municipalities. © 2004 Elsevier B.V. All rights reserved.