Magnetic and transport properties of Ru/Cr doped La (Ba,Ca) Mn O thin films fabricated by the pulsed laser deposition technique on (100) LaAlO 3 substrates have been investigated. Ru-doping reduces both Curie temperature (T C ) and insulator-to-metal temperature (T I M ) in La Ba Ca Mn O thin films: under zero field, La 0 . 7 Ba 0 . 1 Ca 0 . 2 Mn 0 . 9 Ru 0 . 1 O 3 thin films which have T C about 190 K show an insulator-to-metal transition at 75 K. It is likely that Ru-doping creates some antiferromagnetic insulating matrix which separates a basically ferromagnetic background into isolated ferromagnetic domains. In the case of partial substitution of Cr for Mn in La 0 . 9 Ba 0 . 1 MnO 3 thin films, while T C remains almost the same as non-doped films, the magnitude of the magnetization is increased very much due to doping. However, this enhancement does not go along with the enhancement of metallicity: upon doping, T I M shifts to lower temperatures, and the resistivity becomes several orders higher as well. The nature of T I M being far apart from T C in Cr-doped samples are thought to be different from that of Ru-doped ones: it is supposed that the Cr substitution created inhomogeneities resulting in various bonds such as Cr 3 + O Cr 3 + , Mn 3 + O Cr 3 + and Mn O Mn. The observation of T I M far below T C in B-site doping manganite thin films is very anomalous and cannot be explained by double-exchange theory.