Single phase Sn1-xFexO2 (x = 0.1, 0.3 and 0.5) nanoparticles having size in the range 9-17 nm were prepared by a chemical route. XRD analysis of the samples confirmed the formation of cassiterite phase without any impurity. The nanocrystalline nature of the samples and their crystallinity were confirmed by TEM measurements. Raman and Mossbauer spectroscopy studies indicate structural disorder and vacancies in the nanostructures. M-H and M-T data recorded by a SQUID magnetometer show that the samples are essentially paramagnetic with a weak ferromagnetic component. Ferromagnetism is argued to be associated with the vacancies and defects present in the grain boundaries and interfaces of the nanoparticles. (C) 2010 Elsevier B.V. All rights reserved.