Single-laboratory validation data were reviewed by the Expert Review Panel (ERP) of the Stakeholder Panel on Strategic Food Analytical Methods at the AOAC Mid-Year Meeting, March 12-14, 2013, in Rockville, MD. The ERP determined that the data presented met established standard method performance requirements and adopted a method for determination of flavanols and procyanidins (DP 1-10) in cocoa-based ingredients and products by ultra-HPLC as AOAC Official First Action Method 2013.03 on March 14, 2013. The flavanols and procyanidins (DP 1-10) are eluted using a binary gradient (solvents A and B) consisting of 98 + 2 (v/v) acetonitrile-glacial acetic acid (A) and 95 + 3 + 2 (v/v/v) methanol-water-glacial acetic acid (B). The mobile phase is applied to a diol stationary phase. Detection occurs using fluorescence detection. Recovery of flavanols and procyanidins (DP 1-10) from both high- and low-fat matrixes was 98.4-99.8%. Precision was determined for seven different sample types (cocoa extract, cocoa nib, natural cocoa powder, cocoa liquor, alkalized cocoa powder, dark chocolate, and milk chocolate).