Nutritional components of 4 kinds of red seaweeds, Meristotheca papulosa, Chondrus ocellatus, Gracilaria verrucosa, Gigartina tenella, were investigated to elucidate their functionality. Antioxidant activity and nitrite scavenging activity were analyzed from 70% ethanol extracted from these red seaweeds. Large difference in ash contents was found to exhibit among all samples analyzed in this study; $9.8{pm}0.2g/100g$ for Gracilaria verrucosa and Gigartina tenella for $17.8{pm}0.6g/100g$. While its crude fiber content was almost the same as those in other sample within a range between $2.0{pm}0.4g/100g$ and $6.0{pm}0.7g/100g$. Phenolic compounds content of Gracilaria verrucosa was also the highest as $78.4{pm}1.0mg/g$, while the total flavonoids contents of Chondrus ocellatus and Gracilaria verrucosa were $14.9{pm}0.5mg/g$ and $13.9{pm}0.8mg/g$, respectively. These amounts were two folds higher than Meristotheca papulosa and Gigartina tenella. The total content of minerals was the highest in Meristotheca papulosa(12,107.7 mg/kg). The amount of glutamic acid was relatively high despite of small variation in measured levels of composition amino acid ($49.1{sim}125.6mg/g$) for most samples investigated. SOD-like ability was significantly increased with increasing sample concentration, but its activity was lower. Gigartina tenella with highest electron donation ability exhibited increases in activity as $53.96{pm}0.98%$ in concentration of 250 ${mu}g/ml$ and $70.52{pm}1.09%$ in 1000 ${mu}g/ml$, respectively. In case of concentration of 100 ${mu}g/ml$, particularly, the level of hydroxy radical scavenging activity were $57.87{pm}1.70{sim}62.07{pm}0.87%$ which was significantly higher activity than ascorbic acid and BHT. Nitrite scavenging activity was the highest in Gracilaria verrucosa. Its activity was also increased from $24.04{pm}1.9{sim}27.52{pm}0.82%$ in $100{sim}500{mu}g/ml$ concentration tp $34.81{pm}1.36%$ in concentration of 1000 ${mu}g/ml$.