Systemic lupus erythematosus is an autoimmune disease characterized by a pronounced polymorphism of clinical manifestations. Lupus nephritis is the most severe manifestation of the disease. The article presents a retrospective analysis of the cases of systemic lupus erythematosus and assessment of the clinical manifestations of the disease and variants of lupus nephritis in children in the Republics of Belarus and Tatarstan. The authors analyzed 60 cases of systemic lupus erythematosus, lupus nephritis. All patients had at least 4 of the 11 diagnostic criteria proposed by the American College of rheumatology (ACR, 1997), and 35 patients had a morphologically verified nephritis. It was found that the disease in children developed very actively with fast multi-organ involvement and it required aggressive therapy with several immunosuppressive drugs. During follow-up, the percentage of patients with renal damage increased, so renal function should be controlled in all patients with systemic lupus erythematosus, especially with early onset. Lupus nephritis is combined with extrarenal manifestations and it is difficult to diagnose when it begins with kidney damage. The overall survival rate of children with systemic lupus erythematosus is closely related to the severity of renal manifestations. Lupus nephritis is a serious problem that requires early aggressive intervention and continuous maintenance therapy.