S. cerevisiae has evolved the ability to tolerate high concentrations of ethanol, a trait that has contributed to this yeast being a cornerstone of beverage and biofuel industries. The key genes involved in conferring ethanol tolerance in S. cerevisiae are unknown. One strategy used to identify genes conferring ethanol tolerance, was to create ethanol-tolerant (ET) mutants from a laboratory yeast strain and use these to identify ethanol-tolerance conferring loci. Dr. Dragana Stanley (Victoria University) created two ET mutants, a spontaneous (SM) and a chemical (CM) mutant from W303, via adaptive evolution (Stanley 2008). Transcriptome analysis of the resultant ET mutants found that expression levels of hundreds of genes were altered, relative to the parent under ethanol-stress conditions. The primary objective of this thesis was to identify genes that confer ethanol tolerance in SM and CM.