Incontinentia pigmenti is a rare X-linked genodermatosis, often associated with male lethality in utero. Occurrences of this disease in boys have been reported, however, its clinical phenotype has not been well characterized. The purpose of this study was to report on additional instances of incontinentia pigmenti in boys and to review the clinical, laboratory, and molecular characteristics of all published such patients. A retrospective chart review and Medline search using the keywords incontinentia pigmenti, males, and NEMO gene was undertaken. Six new boys with incontinentia pigmenti were found in our database and 36 more were previously reported in the literature. The vesiculo-bullous stage was the most frequent clinical presentation at diagnosis (80%). Fifteen percent of patients had an initial unilateral presentation. Recurrences of this stage were noted in 16%. Stages 2 and 3 of the disease were present in only 72.5% and 75% of patients, respectively. Only 15% of the boys had a documented stage 4. Extracutaneous manifestations were also documented (30% - central nervous system manifestations, 35% - eye involvement, 30% - alopecia, 40% - teeth anomalies). Thirty two percent of boys had peripheral eosinophilia. Only five had evidence of NEMO gene mutation. The male phenotype has clinical features similar to those of the female phenotype. Unilateral presentation is a distinct occurrence in boys, especially in early stages. Anomalies are the most common extracutaneous findings, followed by eye, hair, and central nervous system abnormalities.