Introduction: Although stop-and-go method is recommended for the introduction of methadone by the Japanese guidelines, it may temporarily result in inadequate pain control and/or serious side effects. We report our experience that alleviation of symptoms was achieved by introducing low-dose methadone at an early stage on top of preceding opioids for a patient with refractory cancer pain. Case: Tapentadol and an analgesic adjuvant were given to a 70-year-old man to treat the patient’s old anal pain due to recurrence of rectal cancer at the rectal anastomosis. However, since the pain was poorly controlled, methadone 5 mg was given adjunctively once daily. After methadone medication, remarkable alleviation of pain and improvement in QOL were observed. Discussion: To achieve a safe pain management, adding a small amount of methadone at an early stage, as in this case, may possibly considered.