Brachyonychia is the condition when the width of the nail plate and nail bed is greater than their length. We describe a 21-year-old man who presented with brachyonychia and a 4th middle phalangeal defect on the left foot. Both the 4th metatarsal bones are shorter than the 5th ones on X-ray examination. He had no family history and other anomalies such as facial abnormalities and mental retardation. (Korean J Dermatol 2000;38(1)：142~144)