© 2020 American Entomological Society. All rights reserved.This study makes contributions to the biology of Bombus (Megabombus) argillaceus (Hymenoptera: Apidae) (Scopoli, 1805). A new nest belonging to this species was discovered on the slope of a small spring located on the highlands of Kahramanmaraş Province (southern Turkey). The architecture, material and the contents of the nest were determined. Cocoons of pupae, honey pots and closed egg cells were evaluated in detail. However, it was found that the nest had been modified from a previous wasp nest. Consequently, the architecture and the content of the nest were found to be similar with the literature information about other subgenus Megabombus members. In addition, pollen storage of the nest was investigated and compared with the vegetation of the surrounding area and foraging flower literature data of the species to understand the flower preferences of the colony. We found that the surrounding vegetation represented in the pollen storage was scarce and the dominant pollen source was zygomorphic flowers for the members of this nest.