Nandrolone decanoate (ND) is one of the most commonly abused anabolic androgenic steroids compounds in the world owing to its ability to improve physical performance but its abuse is associated with several adverse effects. The current study was performed to evaluate the effect of recommended and overdose of nandrolone decanoate (ND) for short and long term on the alterations of biochemical markers related to kidney, liver, adrenal, thyroid gland functions and oxidant and antioxidant activities. Sixty male rats were randomly assigned into two major groups. The first was treated with ND for 6 weeks and the second was treated with same drug for 12 weeks. Each of these groups was further subdivided into three sub groups: 1-Control (untreated rats), 2- Rats intraperitoneally injected with ND 3 mg/kg weekly, 3- Rats intraperitoneally injected with ND 15 mg/kg weekly. Administration of high ND dose for either short or long term significantly elevated kidney function biomarkers, liver enzymes both in serum, cytosol and mitochondria, insignificantly increased thyroid function, significantly increased adrenal function while, decreased ACTH. Moreover, oxidative stress biomarkers were significantly upregulated associated with depression in antioxidants activities. Administration of high ND dose for either short or long term as well as the repeated use of recommended ND dose for long term proved to have harmful effects manifested in impairing the functions of kidneys, liver, thyroid and adrenal glands as well as oxidant antioxidant balance.