The influence of temperature and heating rate on the yield and properties of biochar derived from pyrolysis of solid olive mill waste (pomace) was investigated. Three pyrolysis temperatures (430 +/- 10 degrees C, 480 +/- 10 degrees C and 530 +/- 10 degrees C) and 3 heating rates (25 degrees C min(-1), 35 degrees C min(-1) and 45 degrees C min(-1)) were studied. The biochar production was carried out using a vertical downdraft gasifier. Increasing the pyrolysis temperature, and/or the heating rate, the biochar yield lowered, the C content and biochar aromaticity increased and the surface functional groups were reduced. The highest biochar yield was obtained by low pyrolysis temperature (430 +/- 10 degrees C) and low heating rate (25 degrees C min(-1)). This biochar is characterized by a high heating value (31 MJ/kg) that makes it a possible fuel candidate and, in the meantime, due to its high concentration in C (70.2%-84.1%), low electrical conductivity (0.28 dS m(-1)-0.47 dS m(-1)) and the lack of phytotoxicity it is suitable for amendment in agricultural soils and for long term carbon sequestration.