This is the first randomised study comparing buprenorphine-naloxone with methadone for maintenance treatment of opioid dependence. A 17-week, double-blind, double-dummy trial of daily dosing compared buprenorphine-naloxone (8/2 mg and 16/4 mg) with methadone (45 mg and 90 mg) in 268 participants. The percentage of opioid-free urine samples over time did not differ by drug or dosage. The percentage of patients with ≥12 consecutive opioid-negative urine samples did not differ by drug and was significantly greater for patients receiving higher doses of either agent. Induction success, compliance, nonopioid drug use, retention and Addiction Severity Index scores did not differ among groups. Buprenorphine-naloxone is a viable alternative to methadone in clinical practice.