Hamster retina was infected in vitro with irradiated herpes simplex virus type 2. Cells underwent malignant transformation, and when injected subcutaneously into nude mice and hamsters, produced transferable tumors. Transformed cells were found to have HSV antigen as determined by indirect fluorescent staining. In addition, the undifferentiated transformed retinal cells possess neurosecretory granules and retinoic acid receptors and produce growth factor, features similar to those found in spontaneous human retinoblastoma. This is the first neoplasm of ocular tissues induced experimentally by herpes simplex virus (HSV).