To determine whether inappropriate surgical procedures based on an initial misdiagnosis affected recurrence and survival rates, we retrospectively reviewed the surgical treatment and results of 117 patients with high-grade osteosarcomas treated from January 1, 1990 to December 31, 2000. Nine patients had intralesional curettage performed at other institutions based on an erroneous diagnosis of a benign lesion. Two of the nine patients had amputations and seven patients had limb-salvage procedures. Of the 108 patients who were not misdiagnosed, six patients had amputations and 102 patients had limb-salvage procedures. All patients received neoadjuvant therapy. Fifteen of the 117 patients had local recurrences. Patients who had erroneous surgical procedures based on the initial misdiagnosis of osteosarcoma had an increased risk of local recurrence and decreased 10-year survival rate. Response to adjuvant therapy and the amount of previous violation of natural tumor barriers should be evaluated carefully before deciding surgical treatment.