The paper presents the influence of the conditioning of filters used in the gravimetric measurement of particulate matter emission on the mass of the particles. The influence of the time of filter conditioning on the obtained results as well as the influence of the temperature of the sample before the filtering on the measurement uncertainty have been subjected to analysis. In the further part the influence of the ranges of temperatures of the filter conditioning on the mass of the PM sample have been determined as per the standardization for the tests of diesel engines fitted in passenger vehicles, heavy-duty vehicles and buses (regulation R-83 and R-49 respectively). In the final part recommendations have been formulated that allow a reduction of the measurement error.