Visible light responsive C,N-modified porous monolithic titania (MT(f)) has been successfully synthesized. The template-free sol-gel synthesis method accompanied by phase separation and in situ C,N-modification has been used. The molar ratio of water to tetrabutyl titanate (f) in starting solution plays an important role in the porous structure and photoactivity of MT(f). Scanning electron microscopy (SEM) analysis and N(2) adsorption-desorption analysis show that MT(f) possess mesoporous structure as well as macroporous structure. MT(22) has been further characterized by using X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and UV-vis diffuse reflectance spectra (DRS). The results show that both nitrogen and carbon elements exist in MT(22) and result in the visible light photocatalytic activity of MT(22). The observed reaction rate of decolorization of methyl orange is 0.0026 min(-1).