Background: Preterm birth is a major contributor to neonatal morbidity and mortality, especially in rural India where resources are limited. Growth monitoring is essential for timely interventions. The Fenton 2013 growth charts and INTERGROWTH-21st standards differ in methodology and classification, potentially influencing management decisions. This study aimed to compare both the charts in post-natal assessment of preterm babies. Methods: A prospective cohort study was conducted from 2022–2024 at a rural tertiary hospital, including 200 preterm infants (28–36 weeks gestation). Anthropometric parameters (weight, length, head circumference) were recorded from birth to 6 months corrected age and converted to Z-scores using both charts. Extrauterine growth restriction (EUGR) was defined as <10th percentile. Concordance was assessed using Kappa statistics. Results: Most infants (55%) weighed 1.5–2.5 kg at birth; 85% were moderate to late preterm. Fenton charts consistently classified more infants as EUGR compared to INTERGROWTH-21st, particularly in weight. Concordance between charts ranged from moderate to substantial (Kappa 0.45–0.72). Significant discrepancies were observed primarily below the 10th percentile. Conclusion: Growth chart choice substantially impacts preterm growth classification. Fenton charts may overestimate EUGR, risking overtreatment; INTERGROWTH-21st offers a more conservative approach. In resource limited settings, a balanced application of both charts may optimize clinical care and resource allocation.