Until recently, many thought developmental dyslexia was a behavioral disorder that primarily affected reading. In fact, it is a partly heritable condition, the clinical manifestations of which are extremely complex including deficits in reading, working memory, sensorimotor coordination, and early sensory processing. Even though extensive research has characterized these behavioral abnormalities carefully, the biological mechanisms of the clinical manifestations still are poorly understood. Recent research into both the nature of the structural and functional abnormalities in developmental dyslexia and the functional neuroanatomy of reading have rapidly advanced our understanding of the localization of the processes responsible for the signs and symptoms of dyslexia. This paper reviews recent evidence supporting a biological basis for developmental dyslexia.