In this study, the effect of ternary roller mill (four rolls and three gaps) on the selected quality parameters of bulgur was researched. Particle size, colour (L, a, b and YI-values), ash content, hectolitre-weight, yield and loss were evaluated for the roller mill. The first (between first and second rollers: 1.9 mm), second (between second and third rollers: 1.2, 1.0 and 0.8 mm) and third (between third and fourth rollers: 0.4, 0.5 and 0.6 mm) gaps were arranged to determine the optimum parameters. The products obtained were classified as coarse (+/3.5), pilaf (3.5/2.0), medium (2.0/1.0), fine (1.0/0.5) and undersize (0.5/-) using 3.5, 2.0, 1.0 and 0.5 mm circular sieves. The fine bulgur obtained from the roller mill had brighter yellow colour than coarse one. The yield values of samples from the roller mill were obtained between 87.86% and 99.75% at different gap adjustments. When the particle size decreased, the percent ash was decreased from 2.28% to 1.46% due to increase in abrasion effect. The hectolitre-weight values were determined between 70.08 and 81.08 hl/kg. In the ternary roller milling system, coarse, pilaf, medium and fine bulgur could be produced simultaneously. A high production yield and capacity (3500 kg/h) were obtained with low energy consumption (0.00514 kW h/kg). It also supplied uniform particle sizes due to multiple milling stages by preventing the escape of kernels from the gaps. (C) 2007 Elsevier Ltd. All rights reserved.