Herpes simplex virus type 2 (HSV-2) is known to cause aseptic meningitis, which can be recurrent. The diagnosis of HSV-2 infection is suggested when meningitis occurs simultaneously with genital lesions but may be obscure if genital lesions are not present or are not appreciated. Viral culture of the CSF is sometimes positive, but it may also be negative, especially in cases of recurrent disease. We report three cases of HSV meningitis in young women who did not have a history of genital herpetic lesions and for whom genital lesions were not noted on presentation. With use of the polymerase chain reaction (PCR), HSV DNA was detected in CSF from all three patients. The diagnosis of HSV meningitis was further confirmed by a positive culture of CSF in one patient’s case and by demonstration of intrathecal synthesis of HSV antibodies in a second patient’s case. The use of PCR can improve the recognition of HSV meningitis in adults presenting with aseptic meningitis, even in the absence of herpetic lesions.