Hydromorphone is a semi-synthetic opioid agonist which structure is very similar to morphine. It was first synthesized in Germany in 1921, and was introduced into clinical practice by 1926. Nowadays, hydromorphone is used as a second option to morphine in the treatment of both acute and chronic pain, with moderate to high intensity, and in patients presenting intolerable adverse events or inadequate pain relief with morphine. Several studies have demonstrated the efficacy and safety of hydromorphone to relief the oncologic and postoperative pain. Recently, a new formulation using OROS technology was launched in some European countries. This once-a-day formulation provides a convenient and effective option to pain control.