Emerging pharmacogenomics research on addiction to nicotine, alcohol, cocaine, and opiates may soon lead to improved clinical outcomes by tailoring the type, dose and duration of treatment to individual patients' genotypes. To realize the potential of pharmacogenomics in reducing the burden of addiction, several challenges related to clinical integration of novel treatment strategies will need to be addressed concomitantly with ongoing empirical research. These challenges include the preparedness of primary care physicians (PCPs) to incorporate pharmacogenetics into clinical practice, patients' willingness to undergo genetic testing, the resources and infrastructure needed to deliver such services, adequate financing and reimbursement of pharmacogenetic testing, and privacy and antidiscrimination protections sufficient to reassure physicians and patients that genetic testing will not lead to stigmatization and discrimination.