This paper deals with the transpiration of Spathodea nilotica Seem (Bignoniaceae), a small tree native in tropical Africa and cultivated in the State of São Paulo, Brazil, for arborization of streets and ornamental. Transpiration was determined by the so called "cut leaf" method and observations were made on the daily march of total and cuticular transpiration, on the saturation deficits of the leaves used in the determination of the transpiration and on the hydroactive movements of the stomata. Comparation of the daily march of total transpiration curves to the saturation deficits ones of the same leaflets, showed that the two restrictions of total transpiration which the plant presented during the day were caused by lack of water supply in the leaflets. Cuticular transpiration was measured by covering the stomatal (abaxial) face of the leaflets with a layer of vaseline and weighing the cut leaflets in the torsion balance. The daily march of cuticular transpiration compared to the one of total transpiration showed the same results, that is, the restrictions of transpiration during the day were due chiefly to the lack of water supply in the leaflets.