Background: Glutamine dipeptide (Gln) is one of conditionally essential amino acids that have a crucial role in cancer. Objectives: The aim of this study was to investigate the effects of early Gln supplementation in patients with acute myeloid leukemia (AML) receiving intensive chemotherapy, but without bone marrow transplant and regardless of receiving parenteral nutrition. Methods: A randomized control trial was carried out and included 46 AML patients who received high dose chemotherapy. Their ages ranged between 17-65 years. AML patients were randomly allocated as intervention group (Gln group; n=23) and control group (n=23). Gln group received intravenous supplementation with Gln (40 gm) from day 1 to day 5 of chemotherapy, while the patients in the control group received 40 gm per day of a standard amino acid mixture. Clinical end points included the body weight, body mass index, length of hospital stay, days of neutropenia, superoxide anion generation and length of neutropenic fever and serum albumin difference. White blood cells and absolute neutrophil count were done every second day till ANC reached >500µl then superoxide anion generation was measured. Results: Weight loss, length of hospital stay, the mean days of neutropenia and neutropenic fever were significantly lower in the Gln group, whereas the mean superoxide anion generation was found higher comparing to the control group (50 ng/L vs 43ng/L respectively). Complications other than febrile neutropenia were significantly less common in Gln group. Gln supplementation has resulted in significant improvement in serum total protein and serum albumin. Conclusion: This trial suggested that early Gln supplementation regardless receiving parenteral nutrition enhances neutrophil function, maintains nutritional status and decreases hospital stay