The valorization of agro-industrial by-products constitutes a key strategy for the development of sustainable ingredients. In this context, grape pomace, a residue generated during winemaking, represents a potential source of bioactive compounds and nutrients with applications in the food industry. The objective of this study was to evaluate and compare the proximate composition of flours produced from pomaces of two Vitis vinifera varieties (Negra Criolla and Italia), in order to identify relevant nutritional differences. Fresh pomaces were collected, subjected to drying, milling, and subsequent proximate chemical analysis following standardized methods. The results showed no significant differences in ash content (U=3.00; p=0.51), carbohydrates (U=1.00; p=0.12), moisture (t=0.99; p=0.37), crude fiber (t=-1.34; p=0.25), and total energy (t=-1.33; p=0.25). However, significant difference...