Skin fragments implanted subcutaneously into syngeneic mice remained viable and showed cyclic hair growth over a period of months. Embryonic skin differentiated into the various layers of epidermis and corium, producing sebaceous glands and hair follicles. Implants from both embryos and newborn displayed normal hair pigmentation with appearance in metanagen of the yellow bands characteristic of the agouti hair for that genotype. Follicles were observed to pass through the various hair growth stages into a resting period and then later to re-enter the growth cycle. There were departures from normal hair growth, however, with some follicular disorganization, especially in the newborn implants, and with areas showing mixed growth stages instead of the follicular synchronization characteristic of the intact mouse.