The present invention relates to compositions and methods for preparing gamma-linoleic acid (GLA) in safflower plants, particularly from seeds of safflower. Nucleic acid sequences and constructs encoding one or more fatty acid desaturase sequences are used to generate transgenic safflower plants that contain and express one or more of these sequences and produce high levels of GLA in safflower seeds. Provided are transgenic safflower plants and seeds that produce high levels of GLA. Additionally provided are oils produced from seeds of this invention. The invention also relates to methods of treating a variety of diseases including nervous system disorders, inflammatory conditions, cancer and cardiovascular disorders using the oils of this invention.