Evaporative cooling systems are used in broiler houses to reduce the undesirable effects of high temperatures. However, the cooling efficiency of these systems varies according to regional climatic conditions. Therefore, knowledge of cooling efficiency is an important criterion for the prediction of investment and production costs in the design of such systems. In this study, two different broiler houses with the same characteristics were utilised. One broiler house was used to test the traditional fan-pad, while in the other, a water spray evaporative cooling system was tested. The broiler houses were 21.0 m in length, 7.2 m wide and had a floor area of 151.2 m2. The air inlet area in both houses was 6.0 m2 with 1.0×. 3.0 m dimensions on both the long sides of the house. Ventilation was conducted with fans with a total ventilation capacity of 48,000 m3 h−1, each of which was 16,000 m3 h−1 on the short sides. In the period between June and September, the maximum cooling efficiency of the fan-pad system was 79.9% and the maximum temperature depression was 12.5 °C, while for the water spray system, the cooling efficiency was 92.2% and the maximum temperature depression was 17 °C. Cooling efficiency decreased in both systems under high relative humidity conditions. Although the cooling efficiencies differed daily depending on the outdoor conditions, the water spray cooling system was more effective.