AbstractA limited number of cases of thrombotic microangiopathy (TMA) have previously been reported in association with COVID‐19. Our report describes two cases of TMA associated with COVID‐19, one of which was successfully treated with eculizumab. The first case was a 23‐month‐old girl, and the second case was a 9‐month‐old boy. PCR tests for SARS‐CoV‐2 were positive in both cases, and laboratory results showed microangiopathic haemolytic anaemia, thrombocytopenia, and acute kidney injury. No known aetiology for TMA was found in either case. Stool tests for Shigatoxin‐producing Escherichia coli were negative. Coagulation tests, ADAMTS13 activity, serum complement levels, and homocysteine levels were all within the normal range. No known genetic mutation was found, including mutations of complement, diacylglycerol kinase epsilon, and cobalamin C. In the first case, eculizumab was administered due to persistent haemolysis and prolonged anuria. In conclusion, TMA may be associated with COVID‐19 infection. Treatment with eculizumab may be beneficial in selected patients because of the potential activation of the complement system.