One of the main obstacles to therapeutic success in colorectal cancer (CRC) is the development of acquired resistance to treatment with drugs such as 5-fluorouracil (5-FU), the most commonly used drug in CRC patients. Whilst some mechanisms of resistance are well-known, it is clear from the stasis in therapy success rate, that much is still unknown. Here a proteomics approach is taken towards identification using 5-FU resistant sublines of human CRC cell lines generated in-house. Using a multiplexed stable isotope labelling with amino acids in cell culture (SILAC) proteomics strategy, the resistant cell lines, and equivalently passaged 5-FU-sensitive cell lines were compared to parent cell lines grown in Heavy medium using 2D liquid chromatography and Orbitrap Fusion™ Tribrid™ Mass Spectrometry analysis.