Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by multisystem involvement. The renal involvement of SLE may present with hematuria, proteinuria or acute kidney dysfunction. It is well established that pregnancy may trigger the disease activation in patients with SLE. Lupus nephritis (LN) may be diagnosed during pregnancy in very few patients. Preeclampsia is a pregnancy-related disorder characterized by maternal hypertension, proteinuria, and edema and is sometimes complicated by renal dysfunction, which usually occurs in the last trimester of pregnancy. However preeclampsia rarely occurs within 48 h of postpartum. In this report, we present the case of a 20-year-old patient with oliguria, proteinuria, edema, and hypertension who was diagnosed with preeclampsia starting at the 35th week of her first pregnancy. Acute kidney failure developed in the postpartum period after emergency cesarian delivery. Crescentic and diffuse LN was revealed by renal biopsy. While SLE is a risk factor for preeclampsia, LN should be considered in kidney failure in the third trimester or postpartum period.