Patients with nonunion of osteoporotic vertebral compression fractures that are refractory to conservative treatments have persistent back pain, progressive vertebral body collapse and kyphosis, and mobility of the fracture. Although many previous reports have reported vertebral compression fractures treated by balloon kyphoplasty, few data is available on using this method to treat nonunion of vertebral compression fractures. This study evaluated the therapeutic potential of balloon kyphoplasty in the treatment of nonunion of osteoporotic vertebral compression fractures. Twenty-one patients with nonunion of osteoporotic vertebral compression fractures were treated with balloon kyphoplasty. The criteria for diagnosis of nonunion osteoporotic vertebral compression fractures included the following: (1) history of pain for at least 6 months at the fracture site; (2) low T1- and high T2-signal on magnetic resonance images; (3) widening of fracture line on routine radiographs; and (4) movement of the endplate and changes of anterior vertebral heights on hyperextension radiographs. All patients were followed for 9 to 33 months postoperatively (mean 25 months). Statistically significant improvements in the mean postoperative anterior and middle vertebral body heights were observed compared with preoperative values. There was also statistically significant improvement in the mean values for Cobb’s angle, pain (visual analog scale), and the Oswestry Disability Index at the postoperative assessment compared with the preoperative assessment. No statistically significant differences were noted between the postoperative and final follow-up assessment in any of the evaluated efficacy measures. The study suggests that balloon kyphoplasty is an effective technique to treat nonunion of osteoporotic vertebral compression fractures.