The different methods of determining the moisture content result in values with different precision and unbiasedness. The significance of grinding pea seeds during sample preparation on the accuracy of the moisture content was quantified. For working samples with particle sizes of 0-1, 0-2, 0-3, 0-5 and 0-7.5 mm a mean moisture content of 13.56, 13.47, 13.43, 13.39, and 12.25%, respectively and a variance of 0.013, 0.009, 0.008, 0.007 and 0.092%², respectively, were determined with an air-oven method. For working samples with particle sizes of 0-1 mm a mean moisture content of 13.00% and a variance of 0.011%² were determined with a Kari-Fischer-Titration. The significance of over and under estimations due to water loss or gain during sample preparation, chemical reactions during the analysis and residual water in the matrix, the influence of the homogeneity of the moisture content within a sample and the particle size distribution on the precision of a moisture determination will be discussed.