Zinc has a wide spectrum of biological activities and its deficiency has been related to various dysfunctions and alterations of normal cell metabolism. The effects of adequate Zn level (38 mg/kg diet, control) and two low levels that create Zn deficiencies (19 mg/kg diet, 1/2 of control and 3.8 mg/kg diet, 1/10 of control) were investigated in growing male and female rats for 10 weeks. This allowed for evaluation of the effects these Zn levels may have on body weight gain, specific organ weights, blood parameters, and serum concentrations of Zn, Cu and Fe. Rats fed Zn-deficient diets gained less (P<0.05) than the control groups. There was increase (P<0.05) in liver and spleen weights, and a decrease (P<0.05) in testes weight. However, brain, kidney, heart, and lung weights were not affected (P<0.05). Hematological parameters that were decreased (P<0.05) by Zn deficiency included hemoglobin (Hb), total erythrocyte count (TEC) and packed cell volume (PCV) with the magnitude being dose-dependent. Serum concentrations of total protein, globulin, glucose, and high density lipoprotein (HDL) also decreased (P<0.05) in a dose-dependent manner. Zn deficiency increased (P<0.05) total leukocyte count (TLC) and concentrations of serum albumin, total lipids, cholesterol, triglycerides and low density lipoprotein (LDL) in a dose-dependent manner. Serum concentrations of urea and creatinine were, however, not affected (P<0.05) by zinc deficiency. Zn-deficient rats had lower serum concentrations of Zn, Cu and Fe. These results showed that Zn deficiency has negative effects on growth rate, specific organ weights, hematological parameters, and serum levels of Zn, Cu and Fe, especially in rats fed the lowest Zn level.