The paper gives a benefit-cost analysis of ammonia emission control policy in TheNetherlands. Particular care has been given to calculation of the health benefits. Adose-response relationship between air pollution and the number of work loss dayshas been estimated by applying the one-way fixed-effects method to data on workloss days due to illness and average year concentrations of air pollution in 29districts. A significant relationship is found between ammonia (NH3) and thenumber of work loss days (WLDs) and also for sulphate aerosol(SO4). The dose-responserelationship for ammonia has been used to calculate the health benefits ofreducing ammonia deposition in The Netherlands in the periods 1987-1995 and1995-2000. Together with information on other benefits and costs of ammoniaemission control the health benefits are incorporated in a benefit-cost analysis ofrecent and current ammonia control policy in The Netherlands. The benefit cost ratioturns out to be 1/3 from a national point of view and 2/3 if transfrontier benefits areincluded.