We have used a CRMT rocking calorimeter associated with a microbomb to determine the enthalpy of combustion of a sample of mass less than 10 mg of a substance containing iodine. p-Iodobenzoic acid (p-IC6H4CO2H), a candidate as reference material for combustion calorimetry of substances containing iodine, has been investigated. The value of -(3154.2 +/- 1.3) kJ . mol(-1) for its molar enthalpy of combustion obtained with this apparatus is in very good agreement with the only literature value obtained by classical bomb combustion calorimetry.