Abstarct: This study was conducted to investigate the effect of seed size and seed (Zn) treatment on growth and yield traits of three commercial wheat varieties of Gorgan Morvarid, N8720 and N9117 in Autumn 2016 in Gorgan Research and Training Center of Agriculture and Natural Resources. The experiment was arranged as factorial in a randomized complete block design with 3 replications was waeat vallety.The first factor consisted of three levels (Morvarid, N8720 and N9117) and the second factor of seed size consisted of 3 levels (Large, medium and Small) and the third factor.was seed treatment with (Zn). The results showed that in most of the traits of yield components of coarse wheat were higher than those of small seeds in terms of comparison of seed size in 3 cultivars and were superior in plant growth and processes. In this experiment it was found that in some wheat traits such as seedling length, root length, tiller number, plant height, grain yield, coarse size of medium to small size seed and coarse size compared to medium size Smaller had more. There were no significant differences in seed size in the other traits for wheat. It was also found that N8720 had superiority in vegetative and functional traits compared to Morvarid and N9117. In the interaction of cultivar × seed size × seed treatment with (Zn), 1000 seed weight was determined. Morvarid cultivar had large seed size and non seed size was statistically significant and coarse seed size had significant differences with other cultivars. Also, N8720 had a significant difference with size (Medium impregnated with (Zn), small impregnated(zn),and Small amounts of (Zn), There were significant differences Cholera (Large size impregnated with (Zn)and , Medium size without impregnation with (Zn), Were at a statistical level. In N9117, Large seed size, medium-sized, and small-seeded varieties were at the same statistical level and had significant differences with other sizes. It should be noted that the non-seed micronutrients in 3 wheat cultivars were on a statistical level. In studying the interaction of cultivar × seed size × seed treatment with (Zn), the number of shoots was found to be effective on N9117 cultivar and could increase stem number so that seed germination was not affected by (Zn). The figure saw a significant decrease in the number of stems. In Morvarid cultivar, the average seed size was significantly different from the Large seed size. But in the N8720 cultivar, all sizes were at the same statistical level as seeded or non-seeded, interactions had a significant decrease in seed size × seed treatment with (Zn), Seed yield was also significantly decreased only in Large seed size. There was no significant difference between medium and small size.