This is a Phase II, randomized, double-blind, placebo-controlled, intent-to-treat, 2-arm, parallel design, multicenter study to evaluate vigabatrin as a treatment for methamphetamine addiction. The study will involve approximately 180 subjects (90/group) who meet DSM IV criteria for methamphetamine dependence. Subjects will be evaluated for their compliance with protocol inclusion/exclusion criteria during Screening/Baseline Phase, lasting up to 4 weeks.