Hypertrichosis of the eyelashes was first described as "trichomegaly" in the setting of rare congenital syndromes. Recently numerous cases of acquired trichomegaly of the eyelashes have been described, especially in patients with advanced human immunodeficiency virus type I infection. The pathomechanisms leading to acquired trichomegaly remain largely unknown. Direct effects of the virus on the hair follicle, immune dysregulation, and a multifactorial pathogenesis are discussed. We report a case of acquired trichomegaly in advanced HIV-I infection in order to present this unusual clinical finding and other hair problems in AIDS patients. It is suggested that acquired trichomegaly of the eyelashes may act as a useful clinical marker for assessment of severity of HIV-I infection.