Recurrent herpetic keratitis remains a major cause of corneal blindness in developed countries. A fundamental unanwered question regarding herpes simplex virus infection concerns the relationship between the virus and host cell DNA during latency. In the present study DNA was extracted from trigeminal ganglia during both acute and latent infection following ocular inoculation. Extracted, purified DNA was utilized for transfection and for hybridization studies using a32P-labeled HSV-1 DNA probe. DNA extracted during acute infection was complete, linear and non-integrated. Autoradiographic patterns of DNA isolated during latent infection were suggestive of two separate DNA species.