Sn-1 xMnxO2 (x <= 0.11) thin films were fabricated by sol-gel and spin-coated method on Si (1 1 1) substrate. X-ray diffraction revealed that single-phase rutile polycrystalline structure was obtained for x up to about 0.078. Evolution of the lattice parameters and X-ray photoelectron spectroscopy studies confirmed the incorporation of Mn3+ cations into rutile SnO2 lattice. Optical transmission studies show that the band gap energy (E-g) broadens with the increasing of Mn content. Magnetic measurements revealed that all samples exhibit room temperature ferromagnetism (RTFM), which is identified as an intrinsic characteristic. Interestingly, the magnetic moment per Mn atom decreases with the increasing Mn content. The origin of RTFM can be interpreted in terms of the bound magnetic polaron model. (C) 2009 Elsevier B. V. All rights reserved.