Postpartum nephrotic syndrome in a pregnant woman with rheumatoid arthritis in long-standing remission is rare. Systemic lupus erythematosus can remain undiagnosed, especially in the absence of clinical manifestations. We present the case of a 34-year-old woman (gravida 2, para 1) who underwent a lower-segment cesarean section at 34?weeks and 6?days of gestation because she had developed preeclampsia and nephrotic syndrome. The concomitant presence of significant hypoproteinemia, hypoalbuminemia, uremia, elevated creatinine serum levels, hyperuricemia and hypertriglyceridemia is indicative of impaired renal function and nephrotic syndrome. This woman was diagnosed with systemic lupus erythematosus nephritis. It is imperative for clinicians to investigate the exact pathophysiological causes of nephrotic syndrome with onset in the puerperium and implement the appropriate therapeutic regimens.