A study was conducted to assess the eﬀect of evaporative cooling system (ECS) on the performance of sows during summer season and to determine the temperature-humidity index (THI). Ninety one sows were used in the study, 49 sows were housed with ECS throughout gestation (T1) and 42 in conventional housing system all throughout gestation period (T2). The THI in T1 and T2 ranges from 73.31-80.47 and 75.23-82.66 respectively. Results showed that ECS significantly aﬀects the birth weight, back fat thickness at weaning, and weaning to estrous interval of sows but did not have a significant eﬀect on the gestation period, weaning weight, back fat thickness at farrowing, litter size born alive, litter size at weaning, total pigs born, and number of born dead. There was also a 0.75- day diﬀerence in the weaning to estrus interval from T1 was also observed. Partial budget analysis revealed that 25, 634.33 per year per house was added to the net profit of the farm due to the reduction in feed and water costs. Therefore the use of evaporative cooling system to counter the negative eﬀects of summer heat stress on the performance of the gestating sows was economically feasible in a commercial swine production enterprise.