This is a phase 2 clinical trial of citalopram pharmacotherapy for treatment of cocaine dependence. Using a double-blind, randomized controlled design, eligible cocaine dependent patients will be assigned equally to one of three medication conditions: placebo or the Selective serotonin re-uptake inhibitor (SSRI) agent, citalopram at either 20 mg per day or 40 mg per day. It is hypothesized that citalopram will reduce cocaine use and increase periods of sustained abstinence substantially more than placebo. Performance on a set of behavioral tasks of impulsivity will be analyzed as potential predictors of treatment response.