The effect of preharvest CO2 enrichment (1000 μl·liter–1) on postharvest quality of tomato fruit (Lycopersicon esculentum Mill. `Virosa') was studied with an emphasis on soluble sugars, ripening, and mineral composition. High-CO2 fruit had higher concentrations of sucrose, glucose, fructose, and total soluble solids than ambient-CO2 fruit. High-CO2 fruit also ripened more slowly and was characterized by lower respiration and ethylene production rates than ambient-CO2 fruit. Concentrations of N, P, and K were lower in the high-CO2 fruit than in the ambient-CO2 fruit, whereas those of S, Ca, and Mg were the same for both treatments. Preharvest CO2 enrichment of `Virosa' tomato enhances fruit desirability in terms of slower postharvest ripening and higher concentrations of soluble sugars and total soluble solids.