Objective: The purpose of the study was to identify characteristics of injection-drug users that predicted whether subjects would redeem a coupon for free methadone detoxification and to determine whether they were more likely to participate in a 90-day detoxification program than in a 21-day program. Method: A total of 4,390 current heroin users recruited through street based outreach programs in Newark and Jersey City, New Jersey, accepted coupons for either 21 or 90 days (randomly determined) of methadone detoxification after they were interviewed about drug use and sexual behavior. Subjects also gave blood samples for HIV testing. Multiple regression analysis was used to determine variables associated with coupon redemption. Results: Of 4,390 coupons distributed, 58.5 percent were redeemed the 90-day coupons were redeemed at a significantly higher rate (59.9 percent) than the 21-day coupons (56.9 percent). Among coupon redeemers, 43.6 percent had never received formal drug treatment, and 44.9 percent were HIV seropositive. Frequent heroin use, previous drug detoxification, frequent drug injection, cleaning needles with bleach, nonblack race, Hispanic ethnicity, and Newark residence each significantly predicted coupon redemption. Conclusions: Outreach-based coupon distribution may be used to recruit large numbers of never-treated and HIV-infecteddrug users into treatment. The 90-day coupon was more effective in facilitating treatment entry.