Chronic pain has been recognized as a major worldwide health care problem. Today, medical experts and health agencies agree that chronic pain should be treated with the same priority as the disease that caused it, and patients should receive adequate pain relief. To achieve good analgesia, patient adherence to a prescribed pain treatment is of high importance. Patients with chronic pain often do not use their medication as prescribed, but change the frequency of intake. This can result in poor treatment outcomes and may necessitate additional emergency treatment, which increases the overall costs. Factors that influence adherence include knowledge of the disease, realistic treatment expectations, perceived benefit from treatment, side effects, depression, dosing frequency, and attitudes of relatives/significant others toward opioids. Addressing all these factors should ensure a good treatment outcome. Good adherence to pain therapy is associated with improved efficacy in pain relief and quality of life. Opioids have become an integral part of the treatment of moderate to severe chronic noncancer pain. They may cause unpleasant side effects such as nausea, vomiting, and constipation. Patients should be informed adequately about side effects, which should be treated pro-actively to foster adherence to treatment. Signs of tolerance, hyperalgesia, and drug abuse should be monitored as these may occur in some patients. An individualized treatment algorithm with a clear treatment goal and regular treatment reassessment is key for successful treatment. Long-acting opioids offer sustained pain relief over 24 hours with manageable side effects-they simplify treatment thereby supporting treatment adherence.