The increasing prevalence of cocaine use among opioid-dependent participants in methadone treatment has been documented, but there is little information about the quantity-frequency aspects of use. This study examined the cocaine use of methadone maintenance patients to determine amounts and patterns of use as well as use in combination with other drugs. Forty-five cocaine using methadone maintenance patients (78% used i.v.) reported their drug use for each day over the past 7 days after receiving information about their most recent urinalysis test results. Average reported use was 0.23 g cocaine/day on 3.4 days/week. Heroin and cocaine were typically used simultaneously, while only a subset of patients (47%) who used alcohol drank within close proximity to cocaine. Patients who used cocaine with alcohol and/or heroin on the same day (N = 28) reported more cocaine use (M = 1.0 g/week) than patients who used cocaine alone (N = 17; M = 0.49 g/week). The results suggest that methadone maintenance patients generally engage in relatively low dose cocaine use, especially when compared to non opioid dependent patients applying to cocaine treatment programs. The study further shows that patients had clear preferences for drug use combinations, which suggests that interventions for cocaine use might focus on modifying drugs used in combination with cocaine.