Most transplant programs require abstinence of at least 6 months from alcohol and illicit drugs before orthotopic liver transplantation (OLT). However, there are no published data regarding OLT outcomes in patients who are currently on methadone maintenance treatment (MMT) as part of the treatment of their heroin addiction at the time of OLT. The objective of this study is to evaluate our experience regarding the outcome of OLT in patients with end-stage liver disease (ESLD) who were on MMT at the time of OLT. Between March 1993 and May 1999, a total of 185 patients with ESLD underwent OLT at our center. Five transplant recipients (2.7%) had a history of heroin abuse and had undergone drug and alcohol rehabilitation, but could not be weaned off methadone. Pre-OLT status, drug history, perioperative course, compliance with medical therapy, post-OLT follow-up, and patient and allograft survival were analyzed in detail in these patients. All patients on MMT underwent uneventful OLTs. Their compliance with medications and follow-up was excellent. One patient was weaned completely off methadone after OLT. Post-OLT mean hospital stay in this group was 43 ± 25 days. Although the number of patients was small, long-term outcome of liver transplant recipients on MMT appears similar to that of patients not on MMT who underwent OLT during this period. Our results suggest cirrhotic patients on MMT should be considered for OLT if they meet the same psychosocial requirements as patients with alcohol abuse. Furthermore, it is not necessary for patients to be weaned off methadone before OLT.