The electronic and thermoelectric properties of half-heusler compound NiTiSi has been studied using density functional theory and Boltzmann transport theory within the constant relaxation time approximation. NiTiSi is found to be an indirect bandgap semiconductor with a band gap of 0.747 eV. Seebeck coefficient greater than 200μV/K at 1000 K is observed. The calculations suggests that p-type doping can significantly improve the thermoelectric properties of the compound with a maximum value of 0.13 at 1000 K.