The effectiveness of behavioral incentives for improving treatment participation and retention in samples of methadone-maintained (n = 66) and nonmethadone-maintained (n = 76) pregnant drug dependent women was examined. Subjects were randomly assigned to receive $0 (standard care) and $1, $5, or $10/day for attending at least 4 h of interdisciplinary treatment programming during the first 7 consecutive days after transfer from residential to outpatient care, with payment dispensed in the form of gift certificates. Methadone-maintained women attended nearly twice as many full treatment days as those not receiving methadone (5.2 vs 2.8 days; P < 0.001) and were retained in treatment significantly longer (86.4 vs 28.9% active in treatment at 30 days). There was no main effect of incentives and no effect on attendance in methadone patients. However, nonmethadone patients offered higher magnitude incentives ($5/$10) attended 3.3 days out of 7 on average, compared to 2.3 days for those offered $0 or $1 per day (t = 1.73; P < 0.05). The study confirmed that methadone maintenance is a powerful therapeutic adjunct which is associated with significantly better treatment retention and participation in ancillary programming than is abstinence-based treatment. It was also found that modest financial incentives can facilitate treatment participation for abstinence-based patients. However, more potent interventions would be needed to match the effectiveness of methadone in this regard.