The ESR spectra from Mo5+ ions in KTiOPO4 single crystal were studied at 77 K. The ESR spectra reveal two different types of paramagnetic centers, one due to Mo5+ which occupy the Ti(1) position in the crystal and the other, due to Ti3+, formed at position Ti(2) in the crystal. The principal values and direction cosines of the g tensor are reported for the former center.