Two surgical cases of retinal dysplasia are reported. The one is unlateral (left-sided) with microphthalmus and the other bilateral. Chromosome test in the latter case showed no abnormality. In both cases the left eye was enucleated under the clinical diagnosis of retinoblastoma. There was a mass of loose connective tissue behind the lens which was covered by a completely detached retina. Histological examination revealed the presence of branching tubes of primitive retinal structure and large rosettes. The use of the term retinal dysplasia in distinction from Reese's syndrome is mentioned and some morphological characteristics of primitive retinal structure are described.