The incidence of infections in preterm infants is still quite high. In this study, oral care with human breast milk was implemented in risk preterm infants as a precaution. The study was conducted using a quasi-experimental method with a non- equivalent control group and posttest only design in 40 risk preterm infants. The participants were divided into two groups of 20. The data were analyzed using independent t-test and a Wilcoxon test. The results show that this intervention has an effect on the incidence of late-onset sepsis in preterm infants. The effect is based on symptoms: body temperature instability (p = 0.021), C-reactive protein (p = 0.006), and leukocytes (p = 0.020) all indicated differences between the two groups. It is recommended that this practice be adopted as a routine therapy program in perinatology.