Mutagenesis has long been used to increase genetic diversity in different crop species including cultivated flax. In particular, ethyl methane sulfonate (EMS) has been used to create large mutant populations that can be screened using TILLING to identify mutations in specific genes via a reverse genetics approach. Additionally, forward genetics can be used to identify mutants showing interesting phenotypes. Such approaches have been used to identify flax mutants showing modifications in fiber cell wall structure and seed metabolism. The creation and characterization of flax mutant populations is a powerful strategy for gene discovery and for introducing genetic variability in this species that has a narrow genetic base.