The aim of this study is to research the effects of ELF magnetic fields on periodontal tissues and teeth in rats histopathologically. The experiments were performed on 27 male Sprague-Dawley rats, aged 4 months at the beginning of the study, weighing (342.4 +/- 38.89) g and fed with standard pelleted food. The rats were divided into three groups; two experimental and one control (sham). Experimental groups were exposed to 100 and 500 mu T ELF magnetic fields during 10 months, 2 h a day, respectively. Third group was sham that were treated like experimental group except ELF magnetic fields exposure in methacrylate boxes. There was no statistical difference between the experimental groups among all tissues (p>0.05). Alveolar bone, pulp and gingiva there were statistically significant differences among the groups of sham and 1st experimental, sham and 2nd experimental (p<0.05). The statistical difference between the experimental and sham groups in the study makes us to think that ELF magnetic fields may have effects on periodontal tissues and teeth.