TiN has been synthesized by plasma nitridation of single crystalline rutile (TiO2). Nitridation of single crystalline rutile (0 0 1) was performed with microwave plasma of N2 gas. The chemical evidence for TiN formation was determined by x-ray photoelectron spectroscopy and x-ray energy-dispersive spectroscopy with scanning transmission electron microscopy (STEM). Structural characterization from x-ray diffraction patterns and STEM high angle annular dark field images in Z-contrast reveals that TiN consisting of orthogonal domain structure epitaxially forms on rutile substrate. From the orientation relationship, it is understood that nitridation of rutile may proceed along TiO2 to form (1 1 0)-oriented TiN.