Background: Pseudoexfoliation syndrome is one of the most common identifiable causes of open angle glaucoma. It has unknown etiology and pathogenesis. Infection, possibly viral, is one of the proposed pathogenic mechanisms in this condition. In the present study the presence of herpes simplex virus (HSV) in specimens of anterior lens capsule of patients with pseudoexfoliation syndrome has been assessed. Methods: The presence of HSV- DNA was searched by using polymerase chain reaction method in specimens of anterior lens capsule (5 mm diameter) of 50 patients with pseudoexfoliation syndrome (study group) and 50 age-matched patients without the disease (control group) who underwent cataract or combined cataract and glaucoma surgery during a one-year (2006-2007) period in Khalili Hospital, Shiraz, Iran. The results were compared statistically with Chi-square test and independent samples t test using SPSS software (version 11.5). Results: HSV type I DNA was detected in 18% of the patients in the study group compared with 2% in the control group (Chi square test, P = 0.008). The difference between the ranges of intraocular pressure in the two groups was not statistically significant. Conclusion: The presence of HSV type I DNA suggests the possible relationship between the virus and pseudoexfoliation syndrome. It may be a treatable etiology in this multi-factorial disorder and may help to future management of patients; especially to prevent some of the complications in this syndrome.