Abstract: The objective of this study was to evaluate genetic variability and heritability for various seedling traits among S1 families of both maize populations. Three hundred S1 families of two maize populations, viz., UAF Population-1 and UAF Population-2 were evaluated for various seedling vigour traits in two replicates. Highly significant mean squares for almost all the seedling traits indicated the presence of sufficient amount of variability for these traits. Genotypic coefficients of variation were comparatively higher for shoot dry weight, shoot fresh weight and root dry weight in both populations. The estimates of genetic variance were found significant for almost all the seedling traits except for emergence rate index which indicated the presence of exploitable genetic variability. The estimates of broad sense heritability were significant for all the seedling traits except for emergence rate index in UAF Population-1. The most heritable traits were shoot fresh length (h2 = 0.63 and 0.68) and shoot fresh weight (h2 = 0.59 and 0.63) in both populations which suggested that improvement in seedling vigour is possible by using S1 family selection.