To estimate economic injury level "Ell" for the two spotted mite, Tetranycus urticae Koch on cucumber artificial infestation in general average rate 1, 2, 5 and 10 individual mite linch2 were achieved in four separate green plastic houses besides the control one. The experiment was carried out through the two successive seasons, 02-2003 and 03-2004 and with four replicates for each infestation rate, at private farms in Serapium district, Ismailia governorate. The effect of mite on crop yield was evaluated quantitatively. The effect of mite on crop quality was reflected on market's prices. Crop was harvested just after ripping and reaching the suitable marketing size (about 12 cm.long.), weighed and marketed. Management costs, including labour, acaricides and equipment renting price were calculated. Through the first season the yields were 2359, 2066, 1757, and 1323 kg./plastic house, representing 18,28.19,38.93 & 54.0 % reduction in yield under the infestations levels of 1, 2, 5 and 10 mites linch 2 respectively, compared to that of uninfected plastic house that reached 2877 kg./ plastic house. The corresponding figures in the second season were 1843, 1571, 1272, and 1006 kg. I Plastic house representing 20.49, 32.23, 45.13, and 56.6% reductions in yield, compared with that of (2318 kg./ plastic house). Management costs were 171.58 and 157.9 lE throughout the two growing seasons 02-2003 and 03‌ 2004, respectively. The respective fruit prices for kg were 1.1 and 0.92 L.E throughout the two growing seasons 02-2003 and 03-2004, respectively. Economic injury level (Ell) ranged from 1.31 to 1.52 mites linch2. These values of (Ell) could be used as a guideline in the profit of mite control management of cucumber plants under plastic house condition.