Puerperal sepsis is accountable for maternal death worldwide. The health promotion behaviour of postpartum mothers may contribute to preventing puerperal sepsis, which would promote maternal health. The study aims to identify the factors influencing health promotion behaviour on puerperal sepsis among postnatal mothers. A descriptive correlational study design was conducted among 112 postpartum women conveniently selected from Dhaka Medical College Hospital. The measures were personal characteristics questionnaire, perceived benefits questionnaire, perceived barrier, postpartum social support and puerperal sepsis preventive behaviour questionnaire. Data were collected and analyzed by the researcher using descriptive and inferential statistics. Descriptive statistics describe descriptive variables, such as mean, SD, frequency, and percentage. The inferential statistics Pearson's correlation, t-test, and ANOVA were used to describe the relationship among study variables. The mean age of participants was 25.4(SD = 5.14) years old. The socio-demographic characteristics of income (r = 0.24, p = 0.01)., residence (t= -2.12, p = 0.001) and ANC (t= -3.28
p = 0.001) visits were associated with puerperal sepsis preventive behaviour. In addition, the perceived benefit was positively associated (r = 0.62
p = 0.001) with puerperal sepsis preventive behaviour and the perceived barrier was found to be negatively correlated (r=-0.55, p = 0.001). The study findings help increase postpartum mothers' awareness about the benefits of puerperal sepsis preventive behaviour. Findings may be recommended for further experimental study to develop and assess the effect of health promotion guidelines on puerperal sepsis.