This work was conducted to evaluate the effect of season of calving, parity and treatment with Flunixin Meglumine (NSAID) on conception rate in repeat breeder Egyptian Baladi cows and their crosses (Baladi x Friesian). Season of calving was divided into two season cold season (from November to April) and hot season (May to October). A total of 120 cows (n= 60 Baladi cows, n= 60 crossbred cows) were used in the study. 30 Baladi cows were taken and another crossbred was calved during the cold season and was divided into four groups of each group consisting of 15 cows. A total of 30 Baladi cows were also taken and another crossbred was calved during the hot season. It was divided into four groups, each consisting of 15 cows. Fifteen Baladi cows and another crossbred Flunixin Meglumine were treated (1.1 mg / kg BW intramuscular) at fourteenth day from mating in both cold and hot seasons and the other group was as control. The main results showed that the overall average conception rate in Baladi cows was 43.3% higher than that of crossbred cows (30%). Conception rate was higher in Baladi cows calved during the cold season (46.7%) than in cows calved during the hot season (40%). Conception rate of crossbred cows calved during the season was 33.3% higher than those born during the hot season (26.7%). Conception rate in cows in the fourth parity was higher in both Baladi and crossbred cows (83.3 and 50%) respectively compared to the second and third parity. Administration with Flunixin Meglumine resulted in an increase in conception rate of 13.3% in both Baladi and crossbred cows. Concentration of P4 was higher during the first three weeks of conception in the treated Flunixin Meglumine cows than in nontreated cows in both Baladi and crossbred cows. The current study showed the negative effect of the hot season on the rate of conception in cows raised under the conditions of the hot zones, as well as the positive effect of treatment with Flunixin Meglumine on the conception rate in cows. Conception rate was higher during the 4 th parity in Baladi and their crosses. The current study recommends the synchronization of estrous in cows to arrange the births to be during the cold season to avoid the problems of the hot season, especially in southern Egypt, as well as treated with Flunixin Meglumine on the fourteenth day of mating in cows. Future studies on the treatment of Flunixin Meglumine in cows.