I investigate the effect of noise on the amenity value of urban green open spaces in Prague, Czech Republic. First, I use standard hedonic pricing model exploiting cross-sectional and quasi-experimental variation in the apartment price data and then I analyse green open spaces quality inferred from a quantitative spatial model. Results show that increasing size of quiet green open spaces (with noise below 60 dB) by 10% increases local apartment prices by 0.05% and perceived quality of green open spaces by 1.2%. In a counterfactual scenario, if noise in green open spaces decreases by 2 dB, a noise reduction achieved by implementing 30 km/h speed limit in a city, value of apartments would increase by 0.2% due to increased size of accessible quiet green open spaces.