This dataset supports the identification of proteins associated with CHD9 by immunoprecipitation-mass spectrometry (IP-MS) in prostate cancer cells. Endogenous CHD9 was enriched using anti-CHD9 antibodies (with IgG controls), and co-enriched proteins were identified by LC-MS/MS. The resulting protein identifications provide a resource to characterize the CHD9 interactome/associated protein complexes in the cellular context examined in the accompanying study.