OBJECTIVE To describe a case of herpes simplex virus primary infection after a corneal transplantation and to analyse different possible ways by which the infection could have been transmitted. METHODS A corneal transplanted patient for a Fuchs dystrophy complains 10 days postoperatively of a flu-like syndrome with keratouveitis. Donor and recipient viral serologies and a polymerase chain reaction analysis of aqueous humor were performed. RESULTS An herpetic seroconversion is observed with presence of type I herpes simplex virus (HSV I) nucleic acids in the recipient's aqueous humor. The donor herpetic serology is negative. CONCLUSIONS In this patient, the most probable routes of transmission of the virus are a viral reactivation from the trigeminal ganglion of the recipient, the presence of the virus in the corneal transplant or an external contamination.