The environment control of broiler houses must be done adequately to provide good thermal conditions to broilers without wasting energy. The objective of this study was to characterize the thermal environment in two mechanically ventilated broiler houses with a negative pressure ventilation system, one with a cellulose pad evaporative cooling system and the other with misting nozzles for evaporative cooling. The experiment was conducted in Ervália-MG during winter, spring, and summer. The thermal environment was characterized based on the relationship between the temperature observed inside the broiler houses and the temperatures recommended for the thermal comfort of birds of different ages. The recorded data were evaluated using descriptive statistics, and the spatial variation of the average temperature data recorded during the growth phase in both broiler houses was evaluated graphically using contour graphs. During the brooding phase, the temperatures recorded in both broiler houses were above the recommended values (27-30 °C; 24-27 °C; and 21-24 °C, for the 1st; 2nd and 3rd weeks of bird life respectively) during the entire evaluation period. In the growout phase, it was found that during winter and spring, the interior temperature was within the recommended range (15–27 °C), however, in summer, there were periods when the interior temperature was above the comfort range of birds.