Red-grape (Vitis vinifera) residues contain large amounts of polyphenols, especially anthocyanins which act as antioxidants.Red-grape seeds and peel were separated from the pulp and exposed to pre-treatments with ultrasound at 35kHz over 15, 30, 45, 60, 75 y 90min as an alternative to improve the level of polyphenols extraction.Right after the pre-treatment with ultrasound, samples were subjected to an extraction operation by methanol/water (96% v/v) at 60°C over 90min, according to similar conditions previously optimized by Pinelo, M (2004).Both total extractive yield (dry basis) and total polyphenols content were determined for all the extracts obtained from the treated samples, and compared against an extract obtained from a non treated sample.Results showed that at the studied frequency (35kHz), there is a significant effect (α=0.05) of the ultrasound exposure time on both total extractive yield and total polyphenols content.When compared to non treated samples, the exposure to ultrasound at 45min and above showed to significantly (α=0.05)improve the extraction operation by increasing in more than 25% the total extractive yield, except at 75min.Results also showed that ultrasound exposure of the samples at 45, 75 and 90min significantly increased (α=0.05) the total polyphenols content of the extracts in about 65, 50 and 140%, respectively.The effect of ultrasound on the antioxidant capacity of the extracts was also evaluated.Results indicated that ultrasound at 35 kHz decreases the antioxidant capacity of the extracts in about 50%.