Hypopituitarism is a well-known cause of secondary osteoporosis. However, patients receiving surgery for pituitary tumors or parasellar lesions have not been well studied for their bone sequel in Japan. We measured bone mineral density (BMD) and urinary type I collagen N-telopeptide (uNTX) in 35 postoperative patients including 25 with pituitary tumor (PT), 6 with craniopharyngioma (CP), and 4 others who had not been on sex hormone replacement, raloxifene, or bisphosphonate therapy. Compared with patients with PT, patients with CP had lower BMD and higher uNTX. Five out of 6 patients with CP had BMD lower than 80% of young adult mean (YAM), whereas 11 out of 22 patients with PT had BMD less than 80% of YAM. Patients with CP had significantly lower serum levels of gonadotropins, and they also tended to have lower serum levels of sex steroids, although statistically not significantly. Two postoperative patients with CP on sex steroid replacement, who were not included in the current analysis, had normal BMD. Of all the subjects, the prominent difference between patients with normal BMD and normal value of uNTX and patients with low BMD and elevated uNTX value was that the latter received higher dose of hydrocortisone replacement. The present study confirms postsurgical patients with pituitary or parasellar lesions, especially those with CP, are at high risk for osteopenia. In designing replacement therapy for those patients, it is important to consider bone by minimizing the dose of glucocorticoid, including sex steroids, and using other drugs that protect bone.