Nanomaterials have been utilized in medical diagnosis and therapeutics for many years. In this book, we illustrated that modified cell-penetrating peptides (CPPs) combined with nanomaterials noncovalently and raised efficiencies of transductions. We also elucidated their mechanisms of penetrations, cytotoxicities, and cellular trafficking. Mechanisms of complexes rested with the residues modified on CPPs and the zeta potential of CPPs/nanomaterials. Here, we provide an insight that CPPs facilitate the intracellular delivery of fluorescent nanomaterials and are potent tools for drug deliveries.