Data are presented on the diurnal variations in the sugars of wheat leave, as well as on changes in the sugar content of detached and attached leaves, which were taken progressively during the 24 hr. and were starved under the adopted standardized conditions.It was found that in some samples of leaves there was a considerable decrease in their sugars under the conditions of starvation, but on the other hand leaf samples taken either in the first part of a day, or after sunset, usually contained more sugars after starvation than before it. This last observation suggested a considerable hydrolysis of some complex substances in leaves, with the consequent appearance of sugars. From the analysis of the data obtained it was concluded that the observed diurnal variations in the extent of hydrolysis, synthesis, or in translocation of sugars are greatly influenced by the conditions of illumination.