Four newborns presented with isolated radial nerve palsy during the first 2 days of life. In three, there was a history of failure of progression of labor, which may have resulted in prolonged radial nerve compression. Furthermore, three infants had fat necrosis of the upper arm above the elbow, suggestive of compression of the radial nerve in the region of the spiral groove. Significant recovery of function was evident within 1 month in all four infants. The authors review published reports about the rare condition of isolated radial nerve palsy in the newborn.