Objective: Post-hemorrhagic hydrocephalus (PHH) is associated with morbidity and mortality among very low birth weight (VLBW) infants. This study aimed to determine risk factors for PHH among VLBW infants with peri-intraventricular hemorrhage (PIVH). Study Design: This is a population-based cohort of VLBW infants of 24 to 28 weeks gestation, born in Israel from 1995 to 2012. Infants in whom a brain ultrasound was not performed before 28 days or with major congenital malformations were excluded. Univariate and multivariable analyses identified risk factors associated with PHH. Results: The final study cohort comprised 2811 infants with grade 2 or higher PIVH, of whom 610 (21.7%) developed PHH. PHH was independently associated with PIVH severity, with bilateral grade 3 PIVH and PIVH grade 3 and contralateral grade 4 having the highest risks (odds ratio (OR) 12.2, 95% confidence interval (CI) 8.56 to 17.4 and OR 13.7, 95% CI 9.4 to 20.1, respectively). Unilateral grade 3 or 4 PIVH's had moderately increased risks of PHH (OR 3.50, 95% CI 2.26 to 5.42 and OR 3.79, 95% CI 2.35 to 6.12, respectively). PHH was independently associated with increasing gestational age (GA) and with neonatal morbidities including patent ductus arteriosus (OR 1.47, 95% CI 1.15 to 1.88 if medically treated and OR 3.01, 95% CI 2.11 to 4.29 if surgically treated), sepsis (OR 1.79, 95% CI 1.44 to 2.22) and necrotizing enterocolitis (OR 1.60, 95% CI 1.18 to 2.17). Conclusions: Among VLBW infants with PIVH, PHH was independently associated with PIVH severity group, increasing GA and acute neonatal morbidities. Unilateral grade 3 or 4 PIVH was associated with a moderate risk of developing PHH compared with bilateral severe hemorrhages.