The paper presents the results of the research conducted in the period of 1998–2000. They represent a comparison of the elements of the crop structure and yielding of common vetch grown both as pure and mixed crops depending on the number of sown seeds of the pulse. The highest values for the crop structure elements (number of flowers per plant, number of pods per plant, number of seeds in a pod) were observed when common vetch was grown as pure crop. The growing number of the seeds sown caused a significant decrease in the values for the main elements of the crop structure. Spring triticale was found to be the best supporting plant for common vetch grown for seeds. A significantly higher yield of the summer vetch seeds was obtained when 160 seeds per m2 were sown without a supporting plant. The best mixed combination in respect of the yielding was a combination of common vetch (160 seeds per m2) with spring triticale.