Objective: Investigation the clinical et biological feagures of erythema nodosum at the National Hospital of Dermatology and Venerology from 1/2007 to 12/2011. Materiel and Method : The crosssectional study basing on data of patients hospitalized with erythema nodosum from 1/2007 to 12/2011. Result: It was more frequent in woman than man with ratio 6/1(84.6 percent versus 15.4 percent). The peak incidence of Erythema nodosum was between 20-39 years of age with 53.8 percent. The clinical manifestration of erythema nodosum were nodule (61.5 percent), hyperpigmented macule (46.2 percent) located at pretibial area (76.9 percent). Other symptoms were fever (61.5 percent), cough (23.1 percent), arthralgias (46.2 percent), itch (7.7 percent), edema (15.4 percent), and painful (69.2 percent). Hyperleukocytosis was frequent (46.2 percent), elevated transaminases with 23.1 percent. The suspected causes were tubercolosis (15,4 percent), Streptocccus (23,1 percent) and unidentification (46.2 percent). Conclusion: Erythema nodosum was more frequent in woman than man, the peak incidence was between 20-39 years of age. The dinicals and paraclinicals symptoms had value diagnostics.