Rh-doped SrTiO3 (STO:Rh), a visible-light-driven photocatalyst, was examined for the degradation of acetaldehyde as a volatile organic compound under visible light irradiation. Pristine STO:Rh showed slow degradation of acetaldehyde. After ball milling, the ground STO:Rh had a higher specific surface area than before ball milling, and demonstrated a higher degradation rate for acetaldehyde.