Although the composition of strawberry fruit has been extensively studied, especially for the most abundant phenolic compounds, agrimoniin has never been univocally identified as one of the most abundant phenolic compounds in the fruit. In this study agrimoniin was isolated in the fruit of Fragaria vesca and its structure characterized. Furthermore, its presence was definitively established to be the main ellagitannin in both F. vesca and Fragaria ananassa D. fruit. The presence of sanguiin H-6 and lambertianin C as minor compounds was confirmed in both F. vesca and F. ananassa D. samples. For the first time here is reported the full NMR assignments for agrimoniin. These data should represent a point of reference for NMR analysis of this and other structurally related ellagitannins. Finally, the establishment of an HPLC protocol for separation provided information making it possible to avoid confusion with sanguiin H-6, the main ellagitannin in Rubus species, which is also present in strawberries but at a much lower concentration.