A variety of medications are available to treat chronic pain, and a combination of these medications is generally the most effective way to achieve pain relief in patients with longterm pain. Among others, non-steroidal anti-inflammatory drugs (NSAIDS) are the most commonly used group of drugs for the treatment of chronic pain in humans and animals. The fact that NSAIDs have an anti-inflammatory effect is important, as many pain conditions are associated with inflammation-related pain. Therefore, these drugs are among the few drugs available in veterinary medicine that not only relieve the patient's pain, but also treat the pain at its source, i.e. the inflammation. Several NSAIDs are approved for use in dogs worldwide, but only a few are approved for long-term use in cats and only in certain countries. Despite their widespread use and obvious benefit in many cases, NSAIDs are not always sufficiently effective as monotherapy. In addition, there are issues related to the safety and tolerability of their use in dogs and cats. Therefore, the treatment of chronic pain remains a clinical challenge, and indeed chronic pain, such as pain associated with OA, is one of the most common reasons for euthanasia of dogs. There is therefore an urgent need for the development of effective drugs for OA-related pain in dogs and cats. Preclinical and clinical research over the past decades has clearly demonstrated the important role of nerve growth factor (NGF) in sensitising nociceptors in a variety of acute and chronic pain conditions, including postoperative and OA pain. The rationale for the use of anti-NGF therapy in various pain conditions is compelling. Current evidence shows that anti-NGF-MAb therapy has positive analgesic effects in dogs and cats suffering from OA-related pain and is well tolerated for up to three months. In addition, the efficacy of a single injection appears to last at least four to six weeks, and the magnitude of the effect is expected to be equal to or greater than that of NSAIDs. Therefore, anti-NGF-MAb therapy is an alternative to currently available pharmacologic pain treatment options.