Purpose: Enamel defects are serious challenges because of their unaesthetic appearance, dentinal sensitivity and the subsequent susceptibility to dental caries. Apgar index (AI) is used for postnatal, general, neural and behavioural assessment of newborns. The aim of the present study was to investigate the correlation of AI with the enamel defects of primary dentition. Materials and Methods: A total of 181 subjects (95 females and 86 males) aged 3 to 5 years were randomly selected. Subjects with a history of systemic or debilitating diseases or local confounding factors, for example traumatic habits leading to enamel abrasion, were excluded. According to the modified index for developmental enamel defects, visual and tactile examinations of the entire primary dentition (buccal, lingual/palatal and incisal/occlusal) were performed. Teeth with caries lesions and restorations were excluded from the examination. After collection of the data regarding AIs of the subjects, statistical analysis was performed based on the Spearman and Mann-Whitney U tests. Results: Enamel hypoplasia and hypocalcification were negatively correlated with the AI (P 0.05). Moreover, the number of teeth exhibiting enamel defects was significantly lower in subjects with higher AI (P 0.05). The effect of gender on the distribution of enamel defects as a covariate was not statistically significant (P > 0.05). Conclusions: AI is inversely correlated with enamel defects of primary dentition. Both quality and quantity of enamel defects of primary dentition are higher in children with lower AI, delineating a high-risk group demanding more stringent preventive measures. Palabras clave: Apgar index, hypocalcification, hypoplasia, primary dentition