Dioxins are released into the environment as by-products of technological processes, i.a. in the chemical industry, pulp and paper industry, metallurgical industry, textile industry and dyeing industry. Dioxins are a group of compounds recognized by the International Agency for Research on Cancer (IARC) as carcinogens of Group A since 01/06/1997. The carcinogenic action has been demonstrated on animals. Despite stringent obligations arising from the provisions of The Stockholm Convention on Persistent Organic Pollutants on reducing POPs emissions to the environment (including dioxins) emission of these substances is still significant. These compounds often enter the food chain in random or intentional way and accumulate in organisms in the top of the food chain. This leads to the poisoning of the organism and appearance of clinical symptoms. According to the real hazard of poisoning the people, especially employed in the chemical industry, who are exposed to dioxins, research to determine the impact of these xenobiotics on various tissues and organs as well as to develop of effective pharmacological prevention is constantly conducted. Despite of the wide spectrum of the assessment of dioxins biological effects among humans and animals, there are only a few publications evaluating the impact of dioxins on the bone tissue. The main components of the fully functional bone are calcium phosphates and magnesium phosphates. From the proper saturation of bone matrix with salts of these chemical elements (mineralization) depends the hardness and elasticity of the bone. The young bone mineralization is controlled by a group of proteins, from which the most important is osteonectin, osteocalcin and alkaline phosphatase. Many xenobiotics, including dioxins, have a negative influence on the biosynthesis of these proteins. The measurement of calcium and magnesium concentration in bone is one of the methods for assessing bone destruction. The aim of this study was to investigate the effect of 2,3,7,8-tetrachlorodobenzo-p-dioxin (TCDD) in rats on calcium and magnesium levels in bone tissue of their offspring. Moreover the aim of this study was to check whether the administration of the dioxin receptor antagonists – tocopherol and acetylsalicylic acid – can reduce negative effects of dioxin action. Study was performed on 2-day newborns of Buffalo strain rats. Lower levels of calcium and magnesium was found both in cranial vault bones and the knee from newborns of mothers exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin. It was shown that administration of mothers exposed to 2,3,7,8- tetrachlorodibenzo-p-dioxin tocopherol or acetylsalicylic acid prevent decreases in calcium and magnesium concentrations in the bone tissue of the offspring.