Abstract. Mixed seeding is a new approach for forage plant production in Turkey. However, there has been little research into simultaneously seeding multiple crops. The objective of this study was to evaluate the applicability of a seed drill for mixed seeding. Machine performance was determined using pure barley ( L.), pure common vetch ( L.), and mixtures of both seeds at different seed mixture ratios. The indicators of seeding quality, flow uniformity, and seed distribution uniformity across the rows were determined by measurement of seed weights. The other indicator, in-row seed spacing uniformity, was determined by sticky belt tests in controlled laboratory conditions using a computer-aided measurement system. Five different mixture rates of barley:vetch (100:0, 75:25, 50:50, 25:75, and 0:100) and three forward speed values (1.0, 1.5, and 2.0 m s-1) were used in the experiments. While flow evenness and seed distribution uniformity across the rows unit were controlled by the coefficient of variation (CV), in-row seed spacing uniformity was tested based on the variation factor (Vf) and goodness criterion (λ). Based on the experimental results and calculations, it was found that the domestic type combined seed drill could be used effectively for seeding of barley and vetch mixtures at different seed mixture ratios. While the CV values of flow evenness and seed distribution uniformity of each row unit were found to range from 0.8% to 3.7% and from 1.1% to 8.9%, respectively, goodness criterion values ranged from 47.2% to 78.4%. These statistical data give valuable information about the machine performance and the possibility of efficiently using combined seed drills for mixed seeding.