The aim of this study was to compare ultrasound-assisted extraction (USAE) with probe and USAE with bath, using different solvents (ethanol:water), on the extraction of total phenolic compounds (TPC) from tomato pomace and lemon peels by-products:. The TPC after USAE with probe ranged from 1.2- to 3.1-fold and from 1.1- to 2.0-fold more than USAE with bath in tomato and lemon by-products, respectively. The solvent with the highest extraction of TPC from tomato pomace was 100 % ethanol (between 1.2- and 2.6-fold more than the other solvents) while the best solvent in lemon peel was 100% water (between 1.1- and 2.0-fold more). USAE with probe demonstrated to be a clean, efficient, and a green technology for the extraction of TPC from tomato and citrus by-products.