We studied retrospectively 12 children with lupus nephritis divided in two groups according to the treatment made. The patients in the first group received oral 6-methyl-prednisolone alone, until children in the second received too oral cyclophosphamide. At the moment of the admission, no statistical differences were seen between both groups in terms of age, sex, clinical features, renal function, laboratory values and renal pathology based on the classification of the World Health Organisation. Patients in the second group showed a significantly better evolution in mortality (p less than 0.05), improvement of proteinuria and glomerular filtration rate (p less than 0.01 and p less than 0.05 respectively) and laboratory values, without important adverse effects. It seems that the addition of cyclophosphamide in the treatment of patients with lupus nephritis is useful to improve the prognosis of the illness in our patients.