Background and Aims: Low birth weight is a major factor in neonatal morbidity and mortality and constitutes a real public health problem, both in developed and in developing countries. The aims of this study was to determine the frequency of low birth weight and its determinants in newborns during severe preeclampsia at the University Clinics of Kinshasa. Methods: Cross-sectional and analytical study concerning a series of children born to mothers with preeclampsia in the Department of Gynecology between January 1, 2006 and December 31, 2015. Birth weight was measured at birth. Results: The frequency of low birth weight was 60.4% in these children. An increase in SBP and PAD is associated, respectively, with 62.4% (r = 0.624, p <0.001) and 62.5% (r = 0.625, p <0.001) of the decrease in birth weight. After multivariate adjustment, gestational age <28 WA (aOR = 6.75 95% CI: 1.81-9.74, p = 0.013), the αmethyl Dopa + Nifedipine + Diazepam + MgSO4Pritchard scheme (aOR = 2.88 95% CI %: 1.87-4.07, p = 0.011) and maternal complications (aOR = 3.98 95% CI: 1.89-4.44, p = 0.010) were independent determinants of low birth weight of children. Conclusion: The frequency of low birth weight in children born to preeclampsia mothers is high. This frequency is associated with certain risk factors such as gestational age below 37 weeks, the use of diazepam in the treatment regimen and maternal complications.