The implementation of the methadone maintenance treatment programs marked a true milestone in the treatment of those opioid-dependent patients who had met with failure in the different treatment alternatives which had existed up until that time. The purpose of this paper is that of reviewing the scientific evidence regarding the advantages and drawbacks involved in the different drug-related alternatives for use in lieu of methadone for opioid-dependent individuals. To pinpoint the clinical tests conducted, searches were run on Medline (1966-1999), the IDIS (Iowa Drug Information System (1985-1999) and the Cochrane Library 1999 clinical testing database (3rd quarter). Screening and summarization of the literature. Based on the review made, the conclusion was reached that methadone is the chosen drug in substitution treatment for opiate-dependent patients. LAAM came forth as an alternative to methadone for stable patients not requiring close monitoring, although marketing approval was suspended at the recommendation of the Scientific Committee of the European Agency for the Evaluation of Medical Products as of March 2001. Buprenorphene may be one alternative to methadone, however the optimum dosage pattern is as yet unknown. Heroine is the alternative studied to the least degree, although the highly limited number of existing studies indicate that this could be a useful alternative for heroine addicts for whom other maintenance treatments have failed.