Nandrolone decanoate consider as one of the group of anabolic steroids used by athletic with high dose to enhance athletic ability and build muscles. It was found that the use of high dose of these compounds affects the heart, liver and kidneys. Therefore, this study aims to research the histopathological outcome of the drug Nandrolone on the heart, liver and kidneys in adult rabbits. Six adult rabbits were used in this research, and these animals distributed into 2 groups as 3 rabbits in each. The group one considered a control, the second group was given a dose of (10 mg/kg) of nandrolone decanoate\ IM injection for (15 consecutive days). After (24) hours of giving the last dose, the rabbits were slaughtered and samples were taken from the heart, liver and kidney, and they were prepared for histological study by light microscopy. This study showed clear alteration in the structure of the heart muscle, represented in the infiltration of inflammatory cells, vacuolar degeneration, Zenker's necrosis and vascular congestion. In the liver also observed inflammatory cells infiltration, vacuolar degeneration, hyperplasia of lining of bile duct, fibrosis and sinus congestion. In the kidneys, vacuolar degeneration, atrophy and congestion of the glomeruli, expansion of the urinary space and cysts formation were noted. We conclude from the current study that the drug nandrolone has a harmful effect on the histological composition of the heart muscle, liver, kidney in adult rabbits, so the current study recommends limiting the excessive use of this drug.