The south-western regions of Poland are more exposed to industrial emissions containing fluorine than eastern and northern regions. Fluoride is known to accumulate in hard tissues of animals and humans. This paper describes the content of fluoride in mandibles (lower jaws) of deer from two provinces: Western Pomerania and Lubuskie. The fluoride content in lower jaws of deer from Lubuskie was statistically higher compared with fluoride content in Western Pomerania. We concluded that the living conditions of animals in Western Pomerania are more favorable than in Lubuskie. When the concentration of fluoride in bone becomes too high, mineralization defects can occur causing major loss in mechanical resistance despite an increase in bone mass.