Currently, the meals resulting from the processing of canola seeds are mainly used as animal feed. However, the high global production of canola oil generates considerable amounts of this by-product, which has driven research aimed at finding alternative uses for its valorization. This work proposes the analysis, via FTIR, of two by-products: press cake and press cake subjected to ethanol extraction assisted by ultrasound. Canola seeds were provided by Al High Tech (Argentina). These seeds were hydrothermally pretreated in a VZ autoclave (Argentina) for 5 min at 130 °C, dried in a BGH QuickChef microwave oven to 7% moisture (dry basis), and pressed in an IMEGEN screw press (Argentina). The resulting press cake was subjected to ultrasound-assisted extraction (absolute ethanol, 57% amplitude, 60 min, 38°C, solid–solvent ratio 1:28, VCX 500 ultrasonic probe, USA). Press cake samples with and without subsequent extraction were analyzed by means of FTIR-ATR (IRXross, Shimadzu, Japan). The analysis of the spectra allowed for the identification of various bands corresponding to relevant functional groups in both samples. Bands were observed at 1031 cm⁻¹, which were attributed to C–O stretching vibrations, characteristic of polysaccharides. The signals in the region from 2920 to 2930 cm⁻¹ correspond to C–H stretching vibrations, indicative of the presence of polysaccharides. Similarly, the band registered at 1741 cm⁻¹ is related to the presence of carbonyl bonds (C=O) found in lipids, indicating the presence of residual oil. Absorptions near 1230 cm⁻¹ can be attributed to C–H bending vibrations. Finally, peaks were recorded at 3003 cm⁻¹, assigned to C=CH stretching, which may indicate the presence of proteins in the meals. These results suggest that both by-products retain relevant structural components of polysaccharides and proteins, encouraging further analysis aimed at their separation, structural characterization, study of functional properties, and promotion of their valorization in technological applications.