In-doped ZnO (ZnO:In) nanocrystals with various In-contents have been successfully synthesized by vapor phase condensation of mixed source. Hexagonal phase ZnO:In samples with high In-concentration (∼25at.%) were easily obtained and structural phase transformation was observed at ZnO:In nanocrystal with an In-concentration of ∼35at.%. Near band edge (NBE) emission shifted to lower energy side and increase of emission intensity were observed from photoluminescence (PL) measurement, which was explained in terms of the increase of extrinsic carrier concentration. Diffuse-reflectance spectra (DRS) show free-carrier absorption band at 0.6–2.0eV, which corresponds with the PL results.