Current efforts toward improving the effectiveness of drug therapy are increasingly relying on drug-targeting strategies to effectively deliver bioactive molecules to their molecular targets. Pharmaceutical nanocarriers represent a major tool toward this aim, and our efforts have been directed toward achieving nanocarrier-mediated subcellular delivery of drug molecules with mitochondria as the primary subcellular target. Meeting the need for specific subcellular delivery is essential to realizing the full potential of many poorly soluble anticancer drugs. In this article, we report that mitochondria-targeted liposomes significantly improve the apoptotic and cytotoxic action of sclareol, a poorly soluble potential anticancer drug. The results support the broad applicability of our nanocarrier-mediated subcellular targeting approach as a means to improve the effectiveness of certain anticancer therapeutics.