This study aimed to determine the correlation between egg size (length, width, and weight) and hatching weight of white-nest swiftlets (Collocalia fuciphaga) from Buntok, Central Kalimantan. The materials used in this study were 240 fertile eggs of white-nest swiftlets from Buntok, Central Kalimantan. The variables measured were egg length, egg width, egg weight and hatching weight. The correlation between egg size and hatching weight was then evaluated using Pearson's correlation test. The egg length of white-nest swiftlets was ranged from 1.83 to 2.24 cm (mean = 2.01 cm). The egg width of white-nest swiftlets was ranged from 1.20 to 1.40 cm (mean = 1.29 cm). The average egg weight of whitenest swiftlets was ranged from 1.32 to 2.05 g (mean = 1.73 g). The hatching weight of white-nest swiftlets was ranged from 1.03 to 1.67 g (mean = 1.36 g). The results showed that egg length and hatching weight were significantly correlated (r = 0.458, P < 0.001). The correlation between egg width and hatching weight were also significant (r = 0.572, P < 0.001). Moreover, egg weight and hatching weight also indicated a significant correlation (r = 0.754, P < 0.001). Based on the results of this study, it can be concluded that there is a moderate and positive correlation between egg length and hatching weight as well as between egg width and hatching weight of white-nest swiftlets from Buntok, Central Kalimantan. Furthermore, the correlation between egg weight and hatching weight of white-nest swiftlets from Buntok, Central Kalimantan is strong and positive.