[en] Titanium-based half-Heusler compounds (Zr_xHf_1-x)_0.7Ti_0.3NiSn (x=0.3, 0.4, 0.5, 0.6, 0.7) were prepared. The electrical resistivity, Seebeck coefficient, and thermal conductivity of the compounds were measured from room temperature to about 1000 K. The electrical resistivities decrease with increasing temperature. The Seebeck coefficients are negative in the whole temperature range, showing that the majority of charge carriers are electrons. The thermal conductivities increase with increasing temperature. The values at room temperature are around 3.5 W m^-1 K^-1. The maximum value of the thermoelectric figure of merit ZT is 0.32 at around 800 K for (Zr_0.7Hf_0.3)_0.7Ti_0.3NiSn