Abstract Diamond is one of the most promising materials for extreme performance electronic applications, such as high power, high temperature, and high frequency devices. Recent advances in the synthesis of device-quality, single crystal diamond by chemical vapour deposition (CVD) have opened up the possibility to make efficient diamond-based electronic devices. Two important material parameters, which should be maximized, that characterise the performance of diamond in applications of this type are the carrier mobility and the free carrier lifetime. We report an experimental study comparing photocurrent mobility×lifetime ( μτ) products in polycrystalline and single crystal CVD diamond. It is shown that the μτ products of the single crystal samples are 2–3 orders of magnitude higher than those of the polycrystalline samples.