This study was under taken during the seasons oi 2001 and 2002 on twelve years old of Thompson Seedless grapevines. Vines were pruned to 6, 8 or 10 canes with 12 or 14 nodes per each cane under pergola trellis system. The results showed that the percentage of bud burst was affected by the cane length and number of nodes. So, leaving 6 canes with 12 or 14 nodes per cane increased bud burst percentage. since these treatments recorded 81.8% and 79.3% as the mean of two seasons respectively. Vines pruned to 6. 8 or 10 canes with 12 nodes per cane produced a higher bud fertility and leaf area than the other treatments used. While vines pruned to 3 canes with 12 nodes gave a higher internode thickness than the other pruning severity . Number o1 clusters, yield per vine and per feddan were increased by increasing the number 01 nodes. Since, vines pruned to 10 canes with 12 or 14 nodesproduced a higher number of clusters. yield per vine and yield per feddan than the other pruning severity. Concerning berry quality, slight effect was observed on berry weight and diameter due to different pruning severity. Leaving 10 canes with 12 nodes gave somewhat increment in berry weight and diameter. Chlorophyll A and B in berry skin were increased by increasing the levels ol bud load. While living 6 canes with 14 nodes gave a higher value of carotene. TSS was increased by pruning the vines to 8 canes with 14 nodes while acidity was decreased. In relation to pruning severity. increasing bud load on the vine significantly increased total carbohydrates in the canes during dormant season. Vines pruned to 10 canes with 14 nodes showed a higher content ot total carbohydrates in the canes than the other levels of pruning .