We have developed a laboratory experiment that uses high performance liquid chromatography (HPLC) to quantify flavonoid levels in a variety of commercial teas. Specifically, this experiment analyzes a group of flavonoids known as catechins, plant-derived polyphenolic compounds commonly found in many foods and beverages, including green and black tea. HPLC is the most prevalent technique to determine catechin concentrations in plant-based products and this laboratory exercise is ideal for introducing students to chromatographic separations using an analysis method important in agricultural chemistry and nutrition. (Contains 3 figures, 1 table and 4 notes.)