Purpose.To evaluate the presence of herpes simplex virus (HSV) and human papilloma virus (HPV) in pterygia and phenotypically normal conjunctiva and the possible relation between viral presence and clinical information.Methods.Fifty pterygia and respective conjunctival specimens were obtained. A personal and family history was recorded for each patient. HSV and HPV detection and typing were accomplished by polymerase chain reaction amplification of viral sequences. Results were statistically analyzed.Results.HSV (type 1) was detected in 11 (22%), HPV (type 18) in 12 (24%), and both HSV-1 and HPV-18 in 3 (6%) of pterygia. No conjunctival specimen displayed HSV, whereas HPV was detected in four (8%). Postoperative recurrence and history of conjunctivitis were significantly more common in patients with simultaneous detection of HSV and HPV.Conclusion.The fact that HSV was not detected in conjunctival specimens implies a more specific correlation with pterygium, as compared with HPV. The detection of potentially oncogenic viruses, such as HSV and HPV, supports the concept that pterygium can be considered a neoplastic condition. The correlation of postoperative recurrence and a history of conjunctivitis with the simultaneous detection of HPV and HSV, implies a possible viral cooperation affecting the clinical profile of pterygium.