Osteoblastoma is a benign bone tumor of osteoblastic origin. Two cases, an 8-year-old boy and a 24-year-old man, are presented. Both tumors were resected with wide surgical margins and neither patient had adjuvant radiation or chemotherapy. The patients showed no evidence of local recurrence after six to seven years. The clinical, radiological, histological and immunohistochemical features are described. Differential diagnosis and immunohistochemical features potentially useful for refining diagnosis of osteoblastoma are also discussed.