Summary This study carried out in el-zahraa Arab horse stud, Cairo, Egypt. I-First experiment : * investigating the relationship between some hormonal level and maternal behaviour in Arabian mares (20 mare): 1-There were significant difference in prolactin level and progesterone level in blood of mares between promiscuous mothers that had the highest level and other mares subgroups 2-There were significant difference in cortisol level between rejecting that had the highest level and other mare’s subgroups. 3-There were significant difference in first mare standing to groom newborn and total licking time between the three sub group mares, promiscuous mothers stood earlier than other mares to groom the newborn and spent more time in licking, their foals were able to stand and take its first meal quickly than other foals. 4-Rejecting mares remain far away from their foals all time. 5-There were significant difference in maternal aggression between rejecting that had the highest level and other mare’s subgroups during 2nd, 3rd, 4th and 5th month respectively. II-Second experiment : **Regarding the effect of maternal deprivation on physical performance & maintenance behaviour and learning ability , the results revealed that: 1-There were significant difference in growth rate between mothered foals had the highest level and orphan foals. 2-The mean height and length in mothered foals were higher than orphan foals. 3- There were no significant difference in eating time between mothered foals and orphan foals. 4-Mothered foals spent more time lying than orphan foals. 5- The mean frequency of engaged in play, mutual grooming and self-grooming was higher in mothered foals than orphan foals. 6-The mean frequency of mutual grooming was higher in orphan foals than mothered foals 7-There were no significant difference in learning ability between mothered foals and orphan foals. III-Third experiment: ***Studying the influence of weaning method on physiological and behavioural state of foals, the results showed: 1-There were no significant difference in cortisol level between foals weaned in pairs and weaned in group after weaning 2 days post weaning. 2-There were significant difference in activity, vocalization and pawing between pre-weaning foals and post- weaning in all foals. 3-There were insignificant difference in body weight, height and length between foals weaned in pairs and weaned in group. 4-There were insignificant difference in standing and resting behaviour between foals weaned in pairs and weaned in group. 5-There were insignificant difference in body care behaviour between foals weaned in pairs and weaned in group.