A total of 20 male and female opioid dependent cocaine users will participate in this study. This study will be a 8 -week open label study examining the dose-dependent effects of carvedilol (up to 50mg/day) in methadone stabilized patients. The design will have two phases: 1) a four-week "treatment " phase; and 2) a 4 week " taper and detoxification or transfer" phase. Subjects will be cocaine users who are on stable doses of methadone (60 to 140mg/day). Carvedilol dose will be increased from 12.5mg/day to the target dose of 50mg/day as tolerated. At the end of the treatment-phase, subjects will undergo detoxification from methadone over a 2 to 4-week period based on an individual's needs, and they will concurrently be tapered off carvedilol.