One of the complications of pregnancy is the Rh senzibilisation that occurs by the appearance of Rh positive blood in the blood of Rh negative mother. Their passage of the placental barrier results in destruction of fetal erythrocytes, which can cause severe damage. Senzibilisation is most common during fetomaternal bleeding or during transfusion. The mother reacts with the formation of antibodies against the antigens found on fetal erythrocytes and thus becomes sensitized. After any procedure where there is possibility of interfering with fetal and maternal blood, and no preventive measures are applied, senzibilisation, endurance and development of hemolytic fetal and neonatal diseases occur. It is also important to determine the father's Rh status for further treatment and prevention. Prevention is also performed by determining the Indirect Coombs test and applying anti-D immunoglobulin. Antibody titers are based on immunization diagnosis and we estimate the severity of fetal anemia. For this purpose, it is essential to antenatal testing. By first visit to the doctor determine the blood type and the Rh factor and, by means of the indirect Coombs test, determine the presence of antibodies in the circulation. If there is a disease, the estimation is done by amniocentesis and Doppler by measuring the maximum flow rate in the central cerebral artery. Today's therapy consists of intrauterine intravascular transfusion which aims to achieve hematocrit 45%. Phototherapy is used to treat newborn infants with HBFN to reduce bilirubin and exsanguyotransfusion concentrations in order to replace fetal blood with the fresh erythrocytes.