Abstract: Background and Objective: The contribution of acacia to livestock nutrition is important in marginal lands of arid and semi-arid regions, therefore, the current study planned to evaluate the effects of replacement of alfalfa hay with acacia foliage in feeding goats on rumen fermentation, digestibility and growth performance of Ardi goats. Materials and Methods: Goats in-group 1 fed a control diet (C) containing 40% alfalfa hay and 60% concentrate mixture. Goats in groups 2, 3 and 4 fed diets in which 20% (A20), 30% (A30) and 40% (A40) of acacia foliage were replaced as the same percent with alfalfa hay in control diet, respectively. Ammonia concentrations were decreased numerically with acacia contained diets compared to control diet. Results: The highest digestibility values of dry matter (DM), organic matter (OM), crude protein (CP), ether extract (EE), crude fiber (CF) and nitrogen free extract (NFE) were recorded in goats fed C diet followed by A30, A20 and A40 diets. The best nitrogen retention was recorded with the goats fed C diet followed by A30, A20 and A40. There were significant differences on average daily gain between A40 and other diets. The best feed conversion was recorded with C and followed by A20, A30 and A40. Conclusion: The results suggest that the replacement of acacia foliage up 30% instead of alfalfa hay in goat diets without negative impact on the productivity of the animals.