Methamphetamine dependence is a serious public health problem with no pharmacologic treatments currently available. Relapse rates are high in this population. Exposure to cues previously associated with methamphetamine use may induce profound craving in abstinent individuals. Chronic methamphetamine abuse is associated with selective cognitive deficits that may undermine successful participation in psychosocial treatments. Medications which improve cognitive deficits in methamphetamine-dependent individuals may improve abstinence rates, especially in the critical early period of recovery. Modafinil is an atypical stimulant medication with evidence to support its use in treating cocaine dependence and attention deficit/hyperactivity disorder. The proposed studies are designed to evaluate modafinil as a potential treatment for methamphetamine dependence and its cognitive sequelae.