The outgrowth step in yeast transformation protocols is often critical for increasing overall yeast transformation efficiencies. Following treatment of yeast with lithium acetate and polyethylene glycol solutions, it is often necessary to add medium to allow for a period of outgrowth, which normally results in increased cell survival. This is useful when attempting to maximize transformation efficiencies for library screening or transforming yeast with multiple plasmids. YPD Plus is a special formulation of conventional YPD outgrowth medium that increases yeast transformation efficiencies by > 50%. YPD Plus is recommended for mutant yeast strains exhibiting poor growth characteristics that are not amenable to transformation. Simply supplement a yeast transformation reaction mixture with YPD Plus to achieve consistent increases in yeast transformation efficiencies.