The purpose of this research is to distinguish the quantitative determination of phytochemicals in various agricultural products and to optimize an HPLC method for the determination of lycopene, lutein, α-carotene, β-carotene, and cryptoxanthin. Among the different conditions studied, the most suitable ones for our samples were the extraction with hexane/acetone/ethanol (50:25:25, v/v/v), dissolution of the dry extract in tetrahydrofuran/acetonitrile/methanol (15:30:55, v/v/v), injection on a C18 column with methanol/acetonitrile (90:10, v/v) + triethylamine 9 μM as mobile phase, and λdetection=475 nm. The mean percent recovery for the HPLC method were 120.7±4.1% (lycopene), 89.2±3.5% (lutein), 91.2±2.9% (α-carotene), 99.1±4.4% (β-carotene), and 100.0±5.3% (cryptoxanthin). The contents of lutein in the agricultural products were spinach, kiwi, tomato, blueberry, melon, respectively. However, the lycopene contents were the highest in the Black tomato (56.66±7.48 mg/kg) and Jangseong tomato (50.28±5.42 mg/kg). The concentration of β-carotene in all of the agricultural products ranged from 0.07 mg/kg to 65.03 mg/kg. The quercetin content of the agricultural products increased in the order of blueberry (986.57∼1,054.06 mg/100 g), kiwi (44.96∼55.09 mg/100 g), hallabong (31.92∼35.60 mg/100 g), and tomato (26.38∼34.94 mg/100 g). The highest kaempferol content was found in the blueberry (47.79∼76.15 mg/100 g) with results in all of the tested samples varying between 6.54∼48.11 mg/100 g. The total polyphenol contents of the various agricultural products increased in the blueberry (213.60∼229.96 mg/100 g), spinach (112.50∼141.67 mg/100 g) and kiwi (46.49∼70.44 mg/100 g). The total flavonoid content was the highest in both blueberry and spinach. Vitamin C content was detected in kiwi > hallabong > tomato > blueberry, respectively. The total anthocyanin contents (TAC) was detected in the Damyang blueberry and the imported blueberry.