This experiment was carried out to evaluate the effect of using Acacia saligna leaf meal (ASLM) as a non-traditional feedstuff in Mamourah growing hens diets under desert conditions on the performance and economical efficiency of feed. One hundred eighty Mamourah growing hens 10 weeks of age were used in an experiment until 18 weeks of age. The experimental hens were randomly distributed into four equal groups, each group has 45 hens divided into three replicates with 15 hens each. The first group was received a basal diet as a control (0% ASLM) while the second, third and fourth groups were fed 4, 8 and 12% ASLM respectively. The current results showed a significant increase (P < 0.05) in live body weight at 18 weeks of age with groups fed 4 and 8% ASLM compared to the other groups, while the effect of treatment was non-significant with the other ages. The best significant (P < 0.05) values of weight gain and feed conversion ratio were recorded with groups of hens fed 4% and 8% of ASLM in all periods of the experiment. There was a significant (P < 0.05) decrease in feed intake with increasing the level of ASLM in the diet at the experimental periods from 10 to 14 and 10 to 18 weeks of age while this effect was not significant from 14 to 18 weeks of age. The group of hens that received 12% ASLM in the diet showed the lowest performance in comparison with the other groups. On the other hand, the level of 8% ASLM resulted in the best net return, economical efficiency and relative economical efficiency percent and the least feed cost of kg gain. Data of amino acids content of ASLM showed that methionine was the first limiting essential amino acid, while lysine were the second limiting amino acids. From the nutritional and economical efficiency viewpoints, Acacia saligna leaf meal could be used successfully and safely in the formulation of a diet for Mamourah growing hens up to 8% without adversely affecting on their performance under desert conditions.