Background: The studies of series of children with erythema nodosum (EN) are limited and mostly retrospective. Objective: We evaluated the epidemiology, etiology, clinical manifestations, course, and prognosis of EN in children. Methods: Thirty-five children with EN (17 boys, 18 girls; mean age, 8.79 years) have been studied. Four excluded children proved, on biopsy, to have leukocytoclastic vasculitis (n = 3) or eosinophilic cellulitis (n = 1). Results: In 27 of the 35 children (77%), the etiology of EN was established by laboratory investigations. In 25 children the causative factor of EN was an infectious agent (including β-hemolytic streptococcus [n = 17], and Mycobacterium tuberculosis [n = 2]), whereas in 2 patients, EN was associated with Crohn's disease in one and Hodgkin's disease in the other. In 8 of the 35 children (23%) the etiology of EN remained undetermined. The mean duration of the rash was 11.5 days. Recurrences were noted in only 2 children (1 episode in 1 child and 3 episodes in the other). Conclusion: Currently the most common provoking agent of EN in children in Greece is β-hemolytic streptococcus. However, Mycobacterium tuberculosis should still be considered as a cause of the disorder. Also, the course of EN is benign and recurrences are exceptional. (J Am Acad Dermatol 2001;44:17-21.)