iProteinDB is an online integrated protein database and resource tool for providing information on post-translational modifications (PTMs) in Drosophila species. It currently contains phosphoproteomics data for D. melanogaster, D. ananassae, D. pseudoobscura, D. simulans, D. virilis, and D. yakuba. Comparative analysis is available between these species, as well as human and other major model organisms.