We report on an association of idiopathic CD4+ lymphocytopenia (ICL) and juvenile laryngeal papillomatosis (JLP) in a pediatric‐aged patient. Because of a past medical history of recurrent lung infections and severe chickenpox in infancy, immunologic investigations were done at age 6 years. On several occasions, a CD4+lymphocyte count of <300 cells/mm³ was detected, supporting the diagnosis of ICL. During follow‐up, both medical (interferon‐alpha) and surgical treatments of JLP were only partially efficient. Our patient developed disseminated infection with Mycobacterium avium and died at 10 years of age. Human papillomavirus is an important pathogen in pediatric and adult patients with ICL. In pediatric patients with JLP who develop other unusually severe viral or opportunistic infections, immunological investigations should be considered. Pediatr Pulmonol. 2005; 39:281–283. © 2005 Wiley‐Liss, Inc.