The study aims to assess the effect of monosodium glutamate (MSG) in Japanese quail (Coturnix japonica). It was done on one hundred and thirty-four quails were divided into four groups: one control group (C) and three experimental groups that received during 30 days a daily dose of 10 g (E1), 30 g (E2) and 50 g (E3) MSG/kg feed, respectively. It was noticed to the end of the experiment an improvement in growth performance for the group E1, while in groups E2 and E3 higher feed consumption and decreased average daily weight gain was observed. Hematological studies revealed significant changes for the groups E2 (decreased PCV, reduction of Hf/Lf ratio, due to heterophils decrease) and E3 (increased Hf/Lf ratio due to heterophils increase and lymphocytes reduction) compared to the control group (C). Hematobiochemical studies revealed significant increases in blood urea nitrogen (BUN), creatinine and uric acid in quails from E2 and E3. In the kidneys of birds from E2 and E3 birds, was observed a degradation of cortical and medullar cytoarchitecture and also necrosis and vacuolization of proximal and distal convoluted tubules cells were observed. Positive nuclei were showed by P53 staining, both in proximal and distal convoluted tubules, collecting tubules epithelium but also in some of Malpighi corpuscles. Bcl-2 revealed positivity in the cytoplasm of the proximal and distal convoluted tubules cells in varying proportions depending on the group suggesting the prooncogenic potential of MSG in dosages that exceed 30g/kg feed.