This study aimed to assess the accumulation of carotenoids, antioxidant capacity by ABTS method, and color indexes according to the harvest age of three hybrid pumpkin varieties commonly grown in Vietnam. The correlation between them was also evaluated. The results showed that the content of carotenoids (β-carotene, α-carotene, β-cryptoxanthin, zeaxanthin, and lycopene) and retinol activity equivalent (RAE) in the flesh of the hybrid pumpkin varieties reached the highest value during the harvest age from 70 to 75 d. The ABTS antioxidant capacity in the flesh of the F1 pumpkin variety (A1, long fruit) reached the highest value (186.0±10.6 mmol TEAC/100 g at the harvest age of 65 d) compared to the F1 pea pumpkin variety (A2) (174.4±12.0 mmol TEAC/100 g at the harvest age of 70 d) and the F1 hybrid pumpkin variety (A3, round fruit) (156.9±11.1 mmol TEAC/100 g at the harvest age of 75 d). The accumulation of carotenoids positively correlated with the increase of the a* color index but negatively correlated with the L* and b* color indexes. These findings provide information on the accumulation of the carotenoids, the changing trend of the ABTS antioxidant capacity and the color indexes in the flesh of the hybrid pumpkin varieties according to the harvest age (60 - 80 d).