Photocatalytic activity of TiO2 can be further improved by coupling it with other semiconductors and/or carbon nanotubes (CNTs) and create a composite material. SnO2–TiO2/multiwall carbon nanotube (MWCNT) composite catalysts with different molar ratios were prepared and the photocatalytic activities of these samples were evaluated with methylene blue decomposition. The catalysts were synthesized by acid-catalysed sol–gel method. Two series of catalysts were made, one with co-precipitation and the other one with consecutive precipitation method. The samples were characterized by TEM, XRD, BET techniques, respectively. These investigations revealed that some crystalline oxide nanoparticles were successfully bound onto the surface of MWCNTs. Mainly, the MWCNT containing catalysts showed higher photocatalytic activity, and addition of SnO2 enhances the efficiency of photocatalysts. The composites with the ratio of 25–75 (SnO2–TiO2 mol%) with 10 wt% of MWCNTs showed the best performance in photocatalytic test reactions.