Background: Patients are often prescribed opioids at discharge from hospital following surgery. Several studies have shown that a large number of patients do not taper off but continue to use opioids after surgery. Tapering plans and follow-up after discharge may reduce opioid consumption. Methods: This is a single-centre, investigator-initiated, randomized, controlled trial. One hundred and ten preoperative opioid users, scheduled to undergo spine surgery at Aarhus University Hospital, Denmark, are randomized into two groups: 1) an intervention group receiving an individually customized tapering plan at discharge combined with telephone counselling one week after discharge; 2) a control group receiving no tapering plan or telephone counselling. The primary outcome is number of patients exceeding their preoperative intake one month after discharge. Secondary outcomes are withdrawal symptoms during the first month after discharge, number of patients tapering off to zero three months after discharge, patient satisfaction and contacts with the health care system within the first two weeks after discharge. Conclusion: Our study is expected to provide valuable information on opioid tapering after surgery in patients with preoperative opioid use.