Introduction. The microangiopathic antiphospholipid syndrome (MAPS) is a subset of APS comprising those patients presenting with thrombotic microangiopathy and demonstrable antiphospholipid antibodies. Renal involvement occurs frequently in the course of MAPS with clinical symptoms of acute renal failure, hypertension, proteinuria and erythrocyturia. Case report. The report presents the patient with MAPS confirmed by kidney biopsy in the course of undifferentiated connective tissue disease.Conclusion. The authors emphasize the importance of effective anticoagulant treatment in order to inhibit thrombosis and renal damage in the course of MAPS.