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Magnetic and electronic properties of reduced rutile titanium dioxide (TiO2-d) thin films doped by Mn have been investigated. The present sol-gel-grown semiconducting TiO2-d :Mn films exhibit a ferromagnetic behavior at room temperature for a limited range of Mn content. The Mn-doped films have p-type electrical conductivity with the carrier concentration near 1019 cm-3. The observed room-temperature ferromagnetism is believed to be intrinsic but not related to free carriers such as holes. Oxygen vacancies are likely to contribute to the room-temperature ferromagnetism-trapped carriers in oxygen vacancies can mediate a ferromagnetic coupling between neighboring Mn3+ions. The energy band-gap change due to the Mn doping measured by spectroscopic ellipsometry exhibits a red-shift compared to that of the undoped sample at low Mn content. It is explainable interms of strong spin-exchange interactions between Mn ion and the carrier.