Many studies have demonstrated that fruit yield and antioxidant content are significantly determined by cultivar genetics, but abiotic (water supply, etc.) and biotic (mycorrhizae, etc.) factors also have strong affects. A 2-year (2013 and 2014) open-field experiment was conducted to study the effect of mycorrhizae and different water supply levels on yield parameters and carotenoid concentration and composition of processing tomato. Bioactive components were measured by high-performance liquid chromatography (HPLC). Fruits were harvested from green to red maturity stage during two consecutive years. We experienced very large environmental differences between the two years, with particular regard to precipitation and temperature. The effect of irrigation on yield quantity was more significant in 2013 than in 2014. We measured a significantly higher concentration of carotenoids in the second experimental year.