Septic arthritis due to Salmonella in systemic lupus erythematosus is rare. We report a case of septic arthritis by Salmonella enteritidis which occurred during the evolution of systemic lupus erythematosus. A 23-year-old man was diagnosed as suffering from systemic lupus erythematosus. This diagnosis was taken on the basis of general symptoms, skin lesions, hemolytic anemia, thrombocytopenia and glomerulonephritis (class III). He was treated with three methylprednisolone boli related by high-dose regimen of prednisolone. A month and a half later, he presented fever with monoarthritis of the left elbow without any other new sign of underlying systemic disease. Bacteriological examinations isolated S. enteritidis. The patient improved with antibiotics and joint lavage. Feverish monoarthritis in systemic lupus erythematosus should be suspect to be septic arthritis. Appropriate treatment should be promptly instituted to improve the prognosis.