PURPOSE: To describe a case of HSV2 acute retinal necrosis (ARN) diagnosed and monitored with quantitative polymerase chain reaction (PCR) in ocular fluids. DESIGN: Case report. METHODS: Quantitative PCR was performed in the aqueous humor (AH) and vitreous using primers specific for herpes virus. RESULTS: A positive PCR was found for HSV2 in the AH (<100,000,000 viral copies - 8.00 log/ml). After therapy, another anterior chamber tap showed a reduction of the viral load at 4.28 log/ml (19205 copies), confirming the efficacy of the treatment. After six months, PCR on the vitreous still showed the presence of HSV2 viral particles in the eye (3.14 log DNA copies/ml, 1379 copies) although the lesion was healed. CONCLUSIONS: This case demonstrates that PCR is useful to detect viral DNA in AH and vitreous and to monitor viral activity and therapeutic response. Viral DNA persists in ocular fluids for months in the presence of a healed infection