This report is a description of the phenomenon of methadone diversion as it exists now and places it in the context of prior research in this area. The intent here is to clarify issues around methadone diversion and to provide guidance to treatment administrators and program planners regarding efforts they can initiate to monitor this significant phenomenon. After extensive interviewing in the cities of New York, Philadelphia, St. Louis, Miami and San Juan during 1972-73, it was concluded that methadone was readily available on the streets of all five cities. The data indicated that the drug was generally diverted from maintenance programs by the patients themselves. Finally, the study suggests that the majority of the street use of methadone was therapeutically oriented, in that it was typically a technique to check withdrawal or detoxify. (Author/DOW)