Three phenolic acids, (+)catechins, chlorogenic acid, and rutin, were identified and quantified in Mamaki leaves using a liquid chromatograph-mass spectrometer technique. Concentrations of (+)catechins, chlorogenic acid, and rutin varied from 1.1 to 5.0 mg/g 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 30 min contained total antioxidant activity (TAA) between 238 and 259 mg AA/g of tea. Mamaki teas brewed for 1 h and stored at 4 h, 1 d, and 3 d at 4 degrees C had available TAA 293, 271, 172, and 163 mg AA/g of tea leaves, respectively. The concentrations of (+)catechins and rutin in Mamaki leaves are compared to other types of popular teas. Mamaki teas contained relatively low amounts of TAA compared to green teas and Lipton teas.