We investigated whether the outcome of bone disease of primary hyperparathyroidism differs in multiple endocrine neoplasia type 1-associated disease and sporadic hyperparathyroidism at 1-year postoperatively. Multiple endocrine neoplasia type 1/hyperparathyroidism and sporadic hyperparathyroidism patients who underwent parathyroidectomy from 1990 to 2013 and dual-energy x-ray absorptiometry at baseline and 1-year postoperatively were included. Preoperative and postoperative dual-energy x-ray absorptiometry measurements (bone mineral density and Z-score at the lumbar spine, total hip, and femoral neck) were analyzed. We evaluated 14 multiple endocrine neoplasia type 1/hyperparathyroidism and 104 sporadic hyperparathyroidism patients. The preoperative Z-scores at the lumbar spine, total hip, and femoral neck were lower in the multiple endocrine neoplasia type 1/hyperparathyroidism group (P=.05, P=.04, and P=.0081, respectively). Comparison of preoperative and postoperative dual-energy x-ray absorptiometry measurements demonstrated that the multiple endocrine neoplasia type 1/hyperparathyroidism group had a significantly higher Z-score at the lumbar spine (P=.02) at 1year after operation, whereas the sporadic hyperparathyroidism group had a significantly higher Z-score at the lumbar spine, total hip, and femoral neck (P<.0001, P=.0004, and P=.0001) and higher bone mineral density at the lumbar spine (P=.0001). Long-term monitoring of these patients using dual-energy x-ray absorptiometry is required to assess outcomes and facilitate decisions on the timing of operative intervention.