The impact of elevated carbon dioxide concentration (CO2) on the quality of berries, must, and red wine (with special reference to volatile composition, phenolic content, and antioxidant activity) made from Touriga Franca, a native grape variety of Vitis vinifera L. for Port and Douro wine manufacturing grown in the Demarcated Region of Douro, was investigated during 2005 and 2006. Grapevines were grown either in open-top chambers (OTC) with ambient (365 ± 10 ppm) or elevated (500 ± 16 ppm) CO2 or in an outside plot. In general, the increase of CO2 did not affect berry characteristics, especially the total anthocyan and tannin concentrations. However, the total anthocyan and polyphenol concentrations of the red wine were inhibited under elevated CO2. The antioxidant capacity of the wines was determined by DPPH, ABTS, and TBARS assays and, despite the low concentrations of phenolics, the elevated CO2 did not significantly change the total antioxidant capacity of the red wines. Thirty-five volatile compounds belonging to seven chemical groups were identified: C6 alcohols, higher alcohols, esters, terpenols, carbonyl compounds, acids, volatile phenols, and C13 norisoprenoids. Generally, the same volatile compounds were present in all of the wines, but the relative levels varied among the treatments. The effect of elevated CO2 was significant because it was detected as an increase in ethyl 2-methylbutyrate, isoamyl acetate, ethyl hexanoate, ethyl octanoate, butyric acid, and isovaleric acid concentrations and a decrease in ethyl acetate concentration when compared to wines produced in ambient CO2 in 2005. In elevated CO2, wines from 2006 had lower methionol, 1-octanol, and 4-ethylguaiacol and higher ethyl lactate and linalool concentrations. The increase in CO2 did not significantly affect C6 alcohols, citronellol, carbonyl compounds, and β-damascenone concentrations. This study showed that the predicted rise in CO2 did not produce negative effects on the quality of grapes and red wine. Although some of the compounds were slightly affected, the red wine quality remained almost unaffected.