Hydrogenated amorphous silicon-carbon was doped with indium. The films were prepared by reactive magnetron sputtering, using composite targets of silicon and indium in a methane-argon gas mixture. The doping effects of indium on the optical and optoelectronic properties of the films were investigated. The film composition, including the concentration of hydrogen bonded to silicon depends on fractional indium content z. The incorporation of indium in the range of z below 10(-2) yields a compensation of n-type conduction in the undoped film, i.e. the dark conductivity decrease and its activation energy shows a maximum without changing the optical band gap. In the large-z range above 10(-2), the films exhibit alloying behavior as shown by a rapid decrease in the optical bandgap, and a quenching of photoconductivity effect together with an increase in the dark conductivity.