Statement of problem: Dental magnetic attachments has electromagnetic flux that could affect bacterial certain species growth, how would be its effect on a subgingival bacterial specie that had been isolated from both healthy and periodontally affected gingival crevice. Aim of the study is recognition the effect of using dental magnetic attachment on subgingival Black pigmented Bacteroides. Material and Method Ten male patients were selected and received magnetically retained overdenture on mandibular canines. Subgingival samples were collected and were serially diluted. 0.1 ml was transferred from each dilution on the surface of blood agar plates which incubated anaerobically. Black pigmented colonies of bacteroides melaninogenicus were counted and the colony forming units per sample (CFU) was obtained. Results and Conclusion significant decrease in bacteroides counts were observed after one week and a month of magnet fixation. Magnetic dental attachment flux could have an inhibitory effect on subgingival pigmented bacteroides melaninogenicus.