Expression of the epidermal growth factor (EGF-R) in the initial hair growth cycle in a standard strain of laboratory mice, C57-BL/6J-A\spw−j, and a novel mutant termed "downy" was examined through indirect immunofluorescence microscopy. Results show that the EGF-R is expressed similarly in the two types of mouse. The interfollicular epidermis stains intensely and the dermis remains negative throughout the initial cycle of follicle development. The follicle epithelium stains faintly in early anagen stages (1-3c) and then intensely in later anagen stages and for the rest of the initial cycle. The dermal papilla shows no staining in anagen; yet, surprisingly, demonstrates a faint stain during catagen and telogen. These results support findings of other studies that indicate that the EGF-R is not needed to initiate or maintain anagen hair follicles (Green and Couchman, 1984a), yet it is needed for entry into the catagen phase (Murillas et al, 1995). Possible reasons for the faint expression of EGF-R in the dermal papilla in catagen and telogen are discussed.