Phytochemical and vitamin contents of ripe, unripe as well as unripe mango (Mangifera indica) fruits subjected to different ripening methods (use of dark polybag, calcium carbide and hot water) were investigated. The Phytochemicals namely carotenoids, phenols, terpenes, alkaloids, tannins, saponins, phytosterols, flavonoids and glycosides were quantified. Natural ripening (control) increased carotenoids (6.53±0.02mg/100g to 11.46±0.04mg/100g), phenols (15.13±0.02 mg/100g to 25.27±0.02 mg/100g), terpenes (0.08±0.02 mg/100g to 1.77±0.02 mg/100g) but decreased alk aloids (0.61±0.00 mg/100g to 0.53±0.02 mg/100g), tannins (2.06±0.02 mg/100g to 1.08±0.02 mg/100g) and flavonoids (56.80±0.01 mg/100g to 35.88±0.02 mg/100g) among others. Among the naturally ripe (control), unripe and artificially ripened mango fruits, there were no significant differences (p<0.05) in vitamins A, B1, B2, and B3. No significant difference (p<0.05) was obtained in the values of B6 for the naturally and artificially ripened mangoes which ranged from 0.20±0.01 mg/100g in calcium carbide group to 0.28±0.06 mg/100g in hot water group, but each was significantly higher than the value for the unripe mango group (0.13±0.02 mg/100g) The levels of vitamin C (mg/100g) was highest in the unripe fruits (51.06±0.05 mg/100g) followed by hot water treated fruits (50.06±0.05 mg/100g) which did not differ significantly (p<0.05) from the values for polybag treated fruits (49.54±0.19 mg/100g) but each was significantly higher than the value for the naturally ripe fruits (30.90±0.14 mg/100g). In general, it may be concluded that artificial ripening methods increased the phytochemical constituents and vitamin levels in the fruits investigated.