To evaluate seasonal variations in antioxidant components of greenhouse cherry tomatoes, the compositional profile of fruits (“Pomodoro di Pachino”, cv. Naomi F1) harvested at six different times of the year was compared. Among tomato antioxidants, phenolic compounds (naringenin content ranged from 1.84 to 9.04 mg/100 g, rutin from 1.79 to 6.61 mg/100 g) and α-tocopherol (40–1160 μg/100 g) showed the greatest variability. Ascorbic acid (31–71 mg/100 g), carotenoids (8350–15119 μg/100 g), phenolics and α-tocopherol concentration did not show definite seasonal trends, nor correlation with solar radiation or average temperature. Nevertheless, tomatoes harvested in mid-summer were characterized by lowered lycopene levels. Greenhouse growing conditions induced the accumulation of relatively high level of antioxidants for most of the year: one serving of raw tomatoes (100 g) could provide from 50% to 120% of the recommended daily intake of vitamin C, from 13% to 27% of that of vitamin A, from 0.4% to 12% of that of vitamin E, and from 15% to 35% of the flavonoid daily intake estimated for an Italian diet