Boldenone is an anabolic steroid developed for veterinary use. Recently, it is used by bodybuilders in both off-season and pre-contest, where it is well known for increasing vascularity while preparing for a bodybuilding contest. So, the present study was designed to investigate the possible effect of using growth promoter boldenone undecylenate on the rabbit liver tissue. Thirty-two adult New Zealand rabbits were divided into four groups (8 animals each). Control group includes animals that injected intramuscularly with olive oil and dissected after 3 weeks. The experimental groups include animals that receive one, two and three intramuscular injections of 5 mg/kg body weight boldenone, respectively. The animals were dissected after 3, 6 and 9 weeks respectively, where the interval of each dose of boldenon was 3 weeks. Small pieces of the liver tissues were sent for the histopathological examination. Apoptotic p53 and antiapoptotic Bc1-2 proteins were localized immunohistochemically. Histological observations of the liver tissue showed that the sinusoidal congestion was the most prominent feature that extended from the centrilobular to the periportal regions. Hepatocellular vacuolation in the centrilobular region was also detected. Liver immunohistochemical observation showed a significant increase of the apoptotic protein p53 and a significant decrease in the antiapoptotic Bc1-2 proteins. The highest frequency of p53 positive cells was observed in the liver sections of three dose of boldenone injections, while the lowest in control group, also the highest frequency of Bcl-2 positive cells was observed in the liver sections of control group while the lowest in three dose of boldenone injections. The present results investigate that people should be careful if they want to use such steroids to enhance their strength and endurance.