Introduction: Children born small or sick are at risk of death and poor development, but many lack access to preventative follow-up services. We assessed the impact of Pediatric Development Clinics (PDC), which provide structured follow-up after discharge from hospital neonatal care units, on children’s survival, nutrition and development in rural Rwanda. Methods: This quasi-experimental study compared a historic control group to children receiving PDC in Kayonza and Kirehe districts. Study populations in both districts included children born preterm or with birthweight < 2000 g and discharged alive. Kirehe additionally included children with hypoxic ischemic encephalopathy (HIE). Home-based cross-sectional surveys were conducted in Kayonza among children with expected chronological age 11–36 months in 2014 (controls) and 2018 (PDC group) and in Kirehe among children with expected chronological age 17–39 months in 2018 (controls) and 2019 (PDC group). Outcomes were measured using anthropometrics and the Ages and Stages Questionnaires. We used weighted logistic regression to control for confounding and differential non-participation. Results: PDC children (n = 464/812, 57.1%) were significantly more likely to participate in surveys (83.0% vs. 65.5%), have very low birthweight (27.6% vs. 19.0%), and be younger at the survey (26.2 vs. 31.1 months). 6.9% (n = 56) died before the survey. PDC was associated with reduced odds of death (aOR = 0.49, 95% CI: 0.26–0.92) and reduced odds of developmental delay (aOR = 0.48, 95% CI: 0.30–0.77). In Kayonza, PDC was associated with reduced stunting (aOR = 0.52, 95% CI: 0.28–0.98). PDC was not associated with reduced underweight or wasting. Conclusions: PDC was associated with improved survival and development among children born preterm, with low birthweight, or with HIE. Increased access to PDC, scale-up across Rwanda, and implementation of similar services and early intervention in other low-resource settings could support children born small or sick.