Introduction: Haemolytic disease of the fetus and newborn (HDFN) is caused by the destruction of red blood cells of the neonate or fetus by maternal immunoglobulin G (IgG) antibodies. Alloimmune HDFN primarily involves the major blood groups of Rhesus (Rh). A, B, AB, and O, although minor blood group incompatibilities (Kell, Duffy, MNS, P. and Diego systems) can also result in significant disease. Objective: The main objective was to provide insight about the impact of minor blood group incompatibility against ABO and Rh blood group incompatibility in newborns with hyperbilirubinaemia in terms of the demographic data. laboratory values, clinical course, and responses to treatment. Methods: Three hundred fifty-five infants hospitalised with the diagnosis of unconjugated hyperbilirubinaemia (UHB) had data collected retrospectively. The mother and the baby's blood group type as C, c, E. e, Kell, D. d, A, B, O was detected by gel centrifugation method. Patients were divided into 4 groups: group 1, ABO blood group incompatibility: group 2. Rh blood group incompatibility: group 3. ABO+Rh blood group incompatibility: and group 4, minor blood group incompatibility. A total of 355 patients of which 230 (64.7%) were in group 1, 68 (19.1%) were in group 2, 15 (4.2%) were in group 3, and 42 (12%) were in group 4 were evaluated, respectively. Results: Among those with minor blood group incompatibility, 12 (28%), 11 (26%). 9 (21%). 6 (14%), and 4 (9%) patients had "C." "c," "E+c." "E." and "Kell" incompatibilities, respectively. The mean age of diagnosing jaundice (8 +/- 7.5 days) was significantly higher (p=0.015). and the mean haemoglobin and the mean haematocrit levels at admission were lower (p=0.007, p=0.041) in group 4. The rebound elevation of serum bilirubin was remarkably high in group 2 and group 4 (p=0.025). The requirement of intravenous immunglobulin, exchange-erythrocyte transfusions, as well as rehospitalisation for phototherapy, after discharge was significantly higher in group 4. Conclusions: We should keep mind the minor blood group incompatibility in infants who have late hospital admission. prolonged jaundice, prominent anaemia, rebound elevation of serum bilirubin after treatment termination, requirement of exchange and/or erythrocyte transfusions, and increased rehospitalisation rate.