| An experiment was conducted during winter season of 2010-2011 under the condition of desert region in the area at Al-Zubayr in southern Iraq to study the effect of transplant pinching at 3-4 leavers stage on growth and yield of some tomato hybrids grown in plastic tunnels. The experiment included 6 factorial treatment which three determinate hybrids cultivars (Hatouf, Super red and Speedy) and transplant pinching, without transplant pinching. Result could be summarized as follow: Hatouf hybrid was significantly reduced percentage of Flowers at a ratio to(80.07 ,80.10)% also caused a significant increase in number of fruits at a ratio of (57.71, 27.72)%, yield early(129.68 ,30.18)%yield per plant and total yield (75.49 ,19.78)% compared to Superred and Speedy hybrids respectively. Transplant pinching also caused a significant increase in plant length at a ratio 19.46%, stem diameter 16.22%, number of lateral branches 64.28%, number of leaves 67.75%, number of flowers 20.48%, number of fruits 18.14% yield per plant and total yield 27.85% compared to without transplant pinching respectively. The interaction between Hatouf hybrid and transplant pinching gave a significant increases in number of fruits 28.7. yield per plant 2.236kg and total yield 9.838 ton.dounum-1 Keyword: Lycopersicon esculentum Mill, Determinate hybrids, Pinching, Plastic tunnels, Desert region |