The study was performed under strawberry greenhouse between 2007 and 2008. Elevated CO2 was applied to 3 different strawberry tunnels in doses of 500,700 and 1000ppm in march, april and may, respectively. Effect of the applications on a Tetranychus cinnabarinus population, plant yield and quality parameters was studied, with the result that CO2 application were found not to cause any effect likely to decrease T. cinnabarinus population. CO2 enrichment increased fruit firmness and yield but did not significantly contributed to soluble solid content, titratable acid and pH of the fruit. The best performance of CO enrichment was found to be 700 ppm, which increased yield by 66% in 2007 and %32 in 2008 as compared to control tunnels