|The NSAIDs and celecoxib in the treatment of rheumatoid arthritis and osteoarthritis had been used for a long time.However, in vitro animal model, these drugs had been reported that inhibit PGE2 and suppressed the PGE2 production by osteoblasts is involved in the mechanism of bone resorption recently. so the influence of NSAIDs and celecoxib on the patient`s actual bone density was studied. We enrolled 445 patients (Rheumatoid arthritis 256, Osteoarthritis 189), and investigated an use of NSAIDs effects on bone mineral density. All patients included in the study of the patients receiving bisphosphonate. To evaluation of bone mineral density, the Hologic QDR dual energy x ray absorptiometry was regularly performed at intervals of one year, but one-year intervals to observe changes in bone mineral density thought to be too short observation period, two-year trend of change in bone mineral density measured. The NSAIDs administered in each of the patients and the NSAIDs have adverse effects on patients were treated on behalf of celecoxib. Both patients with rheumatoid arthritis, the average steroid prednisolone 10 mg / day was in use, the NSAIDs of the 140 people, the celecoxib was used the 116 patients. The patients with osteoarthritis did not use steroids, NSAIDs was used 106 patients, celecoxib was used 83 patients. In patients with rheumatoid arthritis, the average disease duration of 8 years, the average age is 70 years old and received treatment with NSAIDs or celecoxib period was an average of 4 years, in patients with degenerative arthritis, 7.8 years, 69 years old, was 3 years. During the observation period of the average change of the T-score showed increased in both groups. Patients with rheumatoid arthritis, lumbar portion of 0.11, hip portion 0.01, and patients with degenerative arthritis, lumbar portion 0.15, hip portion 0.06, were increased. Statistically in the groups with the administration of NSAIDs or celecoxib on bone mineral density did not affect. However, The use of bisposphonate was significant (p<0.05). In conclusion, the treatment of NSAIDs or celecoxib did not affect bone mineral density in rheumatoid arthritis patients or patients with degenerative arthritis.