To investigate the response ofDelonix regia seedlings grown in sandy soil to different biofertilizers (Arbascular mycorrhizae fungi, Azotobacter chroorcoccum, Yeast strains and mixture of all inocula) and irrigation intervals (3, 6, or 12 days) on growth and chemical constituents a Pots experiment was conducted using a randomized complete blocks design with three replicates during two successive seasons 2012 and 2013. The results indicated that dual bio-fertilizers led to significant increase in growth characters (Plant height, root length, number of branches/plant,as well as total fresh and dry weights /plant), Microbial populations and AM fungi colonization (%), Enzymatic activities, chemical composition (plant pigments, total carbohydrates,proline content, N, P, K) besides antioxidant enzymes such as Catalase (CAT),and Peroxidase (POD), in comparison with un-inoculated seedlings (as control) and the recommended dose of chemical fertilizers NPK under the same conditions.Generally, these results undoubtedly confirm dual bio-fertilizers could replace the application of chemical fertilizers and consequently improve the quality and quantity of Delonix regia.