Annual crops or exotic trees for cellulose extraction have replaced natural grassland areas of the Brazilian Pampa biome. These activities have been intensified in recent years and may lead to changes in the white grub complex. The objective of this study was to characterize the diversity and abundance of white grubs in cultivated and natural grassland areas of the Brazilian Pampa biome. We conducted samplings in natural grassland and cultivated areas throughout 18 locations in the Brazilian Pampa. Diversity index and nonmetric multidimensional scaling (NMDS) were used to compare the Melolonthidae community within and between cultivated and natural grassland areas. Diloboderus abderus Sturm, Cyclocephala modesta Burmeister, and Plectris sp.5 (Coleoptera: Melolonthidae) were the most abundant taxa, accounting for 49.08% of all white grubs collected from both land use types. Abundance, diversity, and evenness indices were greater in natural grassland than in cultivated areas. The NMDS demonstrated that natural grassland and cultivated areas share similar white grub species assemblages, with 22 species collected in both land use types. Our data suggest that most of the Melolonthidae species collected in the Brazilian Pampa are capable of persisting in cultivated areas. This is the first work characterizing the Melolonthidae community throughout the Brazilian Pampa, which is vital for implementing pest management tactics and conservation of beneficial species.