This 17-week double-blind, placebo controlled randomized pilot clinical trial will provide treatment for 40 cocaine-dependent opioid dependent patients. Participants, aged 18-65 years, will be randomized to receive levetiracetam 3000 mg/day or placebo while concurrently receiving treatment with methadone. Baseline cocaine use will be determined during the first week of treatment participation. (Gossop et al., 1997) The study design will have three overlapping phases that are summarized below: 1) A one week methadone fixed induction (week 1) and flexible methadone stabilization phase (weeks 2-13); 2) an 12-week "treatment" phase (weeks 2-13), consisting of slow titration and stabilization on study medication; and 3) a four week "taper, detoxification or transfer" phase (weeks 13-17).