Transcatheter closure of a patent ductus arteriosus (PDA) is an established technique that may rarely be complicated by severe intravascular hemolysis due to residual shunt. Although conservative management has been reported, the usual approach is to invasively eliminate the residual shunt. We report a case where misjudgment of PDA size and subsequent attempted closure with only one coil led to incomplete closure and residual shunt, which was complicated by severe intramuscular hemolysis. Effectively closing the PDA with an Amplatzer Duct Occluder resulted in immediate resolution of the hemolysis.