Mathematical relationship, in the form of matrix equation, for predicting the compositional distribution along with particle size distribution of the wheat flour stocks following first break milling of wheat, has been defined. Predictions were compared with the actual particle size and compositional distributions obtained by experimental milling. High average accuracy of predicting particle size distribution (97.42%), ash content in the size fractions of the milling output (94.66%) and protein content in the size fractions of the milling output (97.43%) confirms that breakage matrix approach can be successfully used for predicting compositional properties of flour stocks as well as their size distribution. (c) 2005 Elsevier Ltd. All rights reserved.