Abstract: Objective: To evaluate the effects of early prophylaxis phototherapy on hyperbilirubinemia in premature infants. Methods: Thirty-nine premature infants who were hospitalized in 24 h (intervention group) were born between Jan 2004 and Dec 2005. All the infants were treated by phototherapy regardless with or without hyperbilirubinemia and the serum bilirubin level was tested and the peak level was compared with the 41 premature infants who were hospitalized in the 24 h (control group) between Nov 2001 to Nov 2003 and were not treated by phototherapy. Results: The morbidity of intervention group and control group was 10.26% and 51.22% respectively with very significant difference (P<0.005). The serum bilirubin peak level in the intervention group (148.1±50.5) μmol/L was significantly lower than in the control group (222.2±62.5) μmol/L with very significant difference (P<0.001). Conclusions: Early prophylaxis phototherapy on 24 h premature infants may prevent hyperbilirubinemia.