This paper analyses the financial and economic costs and benefits of the large scale National Ecological Network (NEN) nature conservation project in the Netherlands, taking into account transaction costs and land market impacts of different institutional arrangements. The net financial costs associated with achieving the current plan are equivalent with an annual amount 876 per hectare. Of the costs, transaction costs amount about 16% or (sic) 140 per hectare. The substantive land purchases involved in the plan will lead to land price increase of 20%. Nature management by agriculture turns out to be a relatively cheap option.