Summer conditions in the Athens region of Greece cause heat stress to pigs. Transient simulations were conducted using an extension of the AGRISIM program to study the effects of misting, using three conditions in a 300 pigs growing-swine building: (1) no misting; (2) misting up to an indoor relative humidity of 65%; and (3) misting up to an indoor relative humidity of 80%. A 30-year data set of hourly weather data was used. The amount of misting water per hour required was calculated using a new control strategy and found not to exceed 0.8 kg h-1 pig-1 (1.76 lb h-1 pig-1). The simulations confirm that pigs are subjected to heat stress during summer months and that misting can substantially reduce stressful conditions. More specifically, misting up to an inside relative humidity of 80% is justified during July and August, while an upper limit of 65% is reasonable for May, June, and September.