Technical Abstract: Three phenolic acids, (+) catechins, chlorogenic acid, and rutin, were identified and quantified in mamaki leaves (Pipturus albidus) using a liquid chromatograph-mass spectrometer technique. Concentrations of (+) catechins, chlorogenic acid, and rutin varied from 1.1 mg to 5.0 mg per gram of mamaki leaves as determined in the extract using 0.5% acetic acid in 90% aqueous methanol. This study also quantified total antioxidant capacity using the photochemiluminescence method, which was expressed in equivalents to ascorbic acid (AA). Mamaki teas brewed for thirty min contained total antioxidant activity (TAA) between 238 and 259 mg AA/gram of tea. Mamaki teas brewed for one hour and stored at 4 hours, 1 day, and 3 days at 4ºC had available TAA of 293, 271, 172, and 163 mg AA/g of tea leaves, respectively. The concentration of (+) catechins and rutin in mamaki leaves are compared to other types of popular teas. Mamaki teas had similar amounts of TAA compared to green, oolong, or black teas.