Transforming growth Factor-alpha(TGF-alpha) and epidermal growth factor (EGF) are polypeptides which interact with the epidermal growth factor receptor (EGFR) to produce its biological effects. In normal human tissues, its immunocytochemical presence and biological effects have been demonstrated. The aim of the present investigation was to elucidate the immunolocalization of TGF-alpha and EGF in melanocytic nevi. The data presented in this paper focus attention on comparison of TGF-alpha and EGF in intradermal nevus. The expression of TGF-alpha was stronger than EGF in epidermis of melanocytic nevi. In intradermal nevus, TGF-alpha immunoreactivities were present in most of layers of epidermis and a group of nevus cells in dermis were uniformly immunoreactive with minimal cytoplasm. The expression of EGF was found in part of cytoplasm of keratinocytes in the stratum spinosum and stratum granulosum of epidermis. However, keratinocytes in the stratum basale and nevus cells did not demonstrate immunoreactivity for EGF. In epidermal appendages, the staining intensity of EGF was generally weaker than for TGF-alpha except cells in the external root sheath of hair follicle. In conclusion, some regional variations in the intensity of the immunostaining between TGF-alpha and EGF were present in melanocytic nevi. Our results indicate that TGF-alpha may play a role in growth and proliferation of nevus cells.