Leukemias are generally chemosensitive, and a majority of leukemia patients undergo remission. However, since chemotherapy after remission generally causes gross systemic toxicity, patients cannot be administered enough anti-cancer drugs to be completely cured; thus, the rate of long-term disease-free survival remains low. Improved survival requires new strategies to prevent relapse. Molecular targeting therapies are remarkably specific and have been demonstrated to cause no gross systemic toxicity. Molecular targeting drugs for leukemia such as all-trans retinoic acid and imatinib are presently being used in clinical settings, and many other molecular targeting drugs are being evaluated in phase I/II clinical trials. This review presents an overview of some of these drugs.