This work was carried out at the experimental animal center belonging to Faculty of Veterinary Medicine, Benha University through the period from July 2017 to the end of February 2018 to study the effect of season of year on behavior, reproductive and productive performance of breeding rabbits using 24 New Zealand White rabbits (18 females & 6 males) with age of 7 months. These animals were randomly assigned to two equal groups. One of these groups was reared during summer season under hot ambient temperature ranged from 28.7° C to 31.8° C and relative humidity ranged from 44.1 to 65.7 %, while the other group was reared during winter season under temperature ranged from 13° C to 20.4° C and relative humidity ranged from 51.55 to 63.3 %. All rabbits were reared under the same managerial conditions. Does were mated with mature bucks. Rabbits under heat stress during summer season showed low frequency of feeding, grooming and investigatory behaviors and low birth & weaning weight of kids. While there was no effect of the season on gestation length, litter size at birth ,conception rate, kindling rate or mortality rate. from this work, we can conclude that the behavior, reproductive and productive performance were negatively affected during summer season than during winter season.