risk factors of erectile dysfunction in patients receiving methadone maintenance therapy introduction while methadone effectively treats opiate dependence the side effect of erectile dysfunction ed may interfere with treatment adherence and benefitsaim to determine the rate of ed and the associated factors which predict ed in male patients on methadone maintenance therapy mmt in a malaysian populationmain outcome measures the main outcome measures were the international index of erectile function15 iief15 and the beck depression inventory bdimethods a total of 108 participants diagnosed with heroin dependence were assessed we used the structured clinical interview for dsmiv axisi disorders scidi on subjects who received mmt and they were assessed using the iief15 the bdi and measures of other clinical and sociodemographic variablesresults the rate of ed among men on mmt was 685 mild ed 361 mild to moderate ed 222 severe ed 37 the mean age of the participants was 4345 years older age p0002 concurrent illicit heroin use p0024 and having an older partner p0039 were significantly associated with ed following multivariate analysis it was found that older age was the only significant predictor of ed with an adjusted odds ratio of 107 95 ci102116 methadone dose and duration of methadone treatment were not significantly associated with edconclusion ed was highly prevalent among male patients on mmt this suggests that there is a need for routine assessment of sexual function in patients on methadone among the risk factors age was the only factor that was significantly associated with ed the current use of mmt in malaysia in terms of dosage and duration did not pose a significant risk for ed