In the last few years, the use of opioids for cancer pain has rapidly increased and new molecules have been developed. Currently, rapid-onset opioids are widely used in clinical practice for breakthrough cancer pain (BTcP). However, the tolerability of these molecules is still a matter of debate.We describe two cases of rapid-onset opioids misuse that have been recently observed at our palliative care unit.The reported cases are explicative as they occurred in patients suffering from different types of cancer and with different causes of BTcP. Further investigations are needed to identify factors predicting addiction to this new class of molecules.