Hemophilia patients is divided in 3 levels depending on the level of factor VIII/IX: It can be severe if clotting factor is less than 1 percent, moderate if in the range of 1-5 percent and mild when in the range of 5-30 percent. Though the patients with mild hemophilia have many advantages in treatment in comparison with the ones with moderate and severe hemophilia, they still face many challenges in diagnosis. Among three groups of mild, moderate and severe hemophilia, the rate of missed diagnosis and misdiagnosis mainly falls into the group of patients with mild Hemophilia. Therefore, understanding the cause of errors in diagnosis and finding the solution to those problems is one of the concerns in the world as well as in Vietnam.