There are three representative international treatment guidelines for osteoarthritis (OA), each of which has different characteristics. These include the Osteoarthritis Research Society International (OARSI), the National Institute for Health and Clinical Excellence (NICE) from the National Health Service in the United Kingdom, and the American Academy for Orthopaedic Surgeons (AAOS). Among them, the OARSI guidelines are the most frequently revised with new evidence. Besides these international guidelines created by Western countries, there are Japanese OA treatment guidelines which were created by the Japanese Orthopaedic Association based on the OARSI guidelines (part Ⅱ). In some aspects, both guidelines are very similar. However, there are substantial differences, especially with respect to hyaluronic acid injection and supplements including glucosamine and chondroitin sulfate. In this paper, the newest 2014 OARSI treatment guidelines (part Ⅳ) are introduced in which the Author was a committee member as the Asian representative. There is also discussion about the present status of OA treatment in Western and Asian countries, especially when comparing between corticosteroid and hyaluronan intraarticular injections, and that between non-selective non-steroidal anti-inflammatory drugs (NSAIDs) and cyclooxygenase-2 inhibitors, and the recent status of acetaminophen and topical NSAIDs.