Many anticancer drugs attack rapidly dividing cells, including not only malignant cells but also hair follicle cells, and induce alopecia. Chemotherapy-induced alopecia (CIA) is an emotionally distressing side effect of cancer chemotherapy. There is currently no useful preventive therapy for CIA. We have previously constructed anti-death rFNK protein from rat Bcl-x(L) by site-directed mutagenesis to strengthen cytoprotective activity. When fused to the protein transduction domain (PTD) of HIV/Tat, the fusion protein PTD (TAT)-rFNK successfully entered cells from the outside in vitro and in vivo to exhibit anti-death activity against apoptosis and necrosis. Here, we show that topical application of FNK protected against CIA in a newborn rat model. The protective activity against hair-loss was observed in 30-1000 nM TAT-rFNK administrative groups in a dose-dependent manner. Furthermore, a human version of FNK (hFNK) fused to other PTD peptides exhibited a protective ability. These results suggest that PTD-FNK possesses protective activity against CIA and is not restricted to a sequence of PTD peptides or species of FNK. Thus, PTD-FNK represents potential to develop a useful method for preventing CIA in cancer patients.