The experiment was conducted with the objective of examining the effects of high molybdenum on the cell cycle and apoptosis of kidney in broilers by the methods of flow cytometry. Three hundred 1-day-old Avian broilers were randomly divided into four groups, and fed on diets as follows: control diet (Mo 13 mg/kg) and high molybdenum diets (Mo 500 mg/kg, high molybdenum group I; Mo 1,000 mg/kg, high molybdenum group II; Mo 1,500 mg/kg, high molybdenum group III) for 6 weeks. The results showed that the relative weight of kidney were higher (P < 0.05 or P < 0.01), and the cellular percentages of G(0)/G(1) phase were lower, and cellular percentages of S phase and the proliferating index were higher in high molybdenum groups II and III than in control group (P < 0.01). The percentage of renal cell apoptosis was increased in high molybdenum groups II and III when compared with that of control group (P < 0.01). Immunohistochemical test showed that there were increased frequencies of positive cells containing Bax protein and decreased frequencies of positive cells containing Bcl-2 protein in high molybdenum groups II and III. It was concluded that dietary high molybdenum (1,000 mg/kg and 1,500 mg/kg) impaired the progression of renal cells from S phase to G(2)M phase obviously and induced renal cell apoptosis.