The chemical compositions of the flower and leaf essential oil of Cassia fistula L. were examined by GC and GC/MS. Forty-four compounds were identified representing 92.6% and 90.7% of the flower and leaf oil, respectively. The main components of the flower oil were (E)-nerolidol (38.0%), and 2-hexadecanone (17.0%), while the leaf oil consisted mainly of phytol (16.1%).