Alendronate sodium is a potent inhibitor of bone resorption which has been effectively used to control osteolysis, and to treat Paget's disease and osteoporosis. The objective of this study was to investigate the effect of alendronate sodium, systemically induced in the treatment of patients with periodontitis. Twenty-four adult periodontitis patients were included in the study (for six months) and were divided into two groups. Group I, included twelve patients who received one tablet of fosamax (alendronate sodium, MSD) every morning for six months. Group II, also included twelve patients who received no drug during the study period. All patients received initial periodontal therapy. Bone mineral density (BMD) of the maxilla and mandible was measured for all subjects using a dual energy absorptiometer (DEXA) at the beginning of the study and at the end of six months using DPX. MD Scanner. Clinical periodontal measurements were carried out for all patients at the initial appointment and six months later in the form of pocket depth, attachment level and gingival index. A statistically significant difference in bone density (P < 0.001) was observed favouring the alendronate group (Group I). Alendronate sodium had no effect on the clinical parameters and could play an important role as an adjunct to conventional periodontal therapy in management of periodontal diseases.