To investigate the interactive effects of elevated CO2(e[CO2]), nitrogen (N) supply and irrigation regimes on tomato (Solanum lycopersicumL., cv. Elin) yield, water use efficiency (WUE) and fruit quality, potted plants were grown in glasshouse compartments with CO(2)concentration of 400 and 800 ppm, separately, with 0 or 0.5 g N kg(-1)soil. Since anthesis, the plants were subjected to three irrigation levels (I1, I2 and I3 - irrigated to 35% soil water content (SWC, v/v), 30% SWC and 25% SWC, respectively). e[CO2] had a slight effect on fruit yield and sugar, acid, soluble solids content (SSC) and total antioxidant capacity (TAC) in fruit juice, while it enhanced Mn, B and Fe contents in fruit biomass. WUE was improved bye[CO2] and I3 irrigation, but reduced by N supply. Though N supply lowered SSC, TAC, K+, Ca(2+)and Mg(2+)in fruit juice, it increased micro-nutrient (Mn, Mo, Cu, Zn, Fe) contents in fruit biomass. Most notably, principal component analysis revealed the best comprehensive quality of tomato fruits was found for plants grown undere[CO2] with sufficient irrigation and N supply, suggesting optimal irrigation and N fertilization are essential for good tomato quality in glasshouse production under CO2-enriched environment.