Erythema nodosum (EN) has been associated with various infectious and noninfectious diseases. A total of 39 EN patients seen between May 2005 and February 2012 were evaluated retrospectively in this study. The etiology of EN was established in 22 of the 39 children (56.4%). Streptococcal infection was the most common cause (23%), followed by tularemia (10.2%) and tuberculosis (latent tuberculosis infection (LTBI) 5%, pulmonary tuberculosis 2.5%). Miscellaneous conditions were as follows: Behçet disease (2.5%), cytomegalovirus (CMV) (2.5%), Giardia lamblia infection (2.5%), and sarcoidosis (2.5%). Four cases had double diagnoses as follows: streptococcal infection plus Mycoplasma pneumoniae, streptococcal infection plus LTBI, streptococcal infection plus Chlamydophila pneumoniae, and tularemia plus LTBI. Streptococcal infections are the most common causative factors of EN among children in our setting. In some cases, either of two diagnoses may induce EN. Etiologic factors should be investigated for the diagnosis and specific treatment of the underlying diseases.