One mature blade of each squash plant was continuously labeled with (14)CO(2) for 15, 30, or 70 minutes in light. The ethanol soluble materials from serial sections of petioles were extracted and separated by paper chromatography. The ratios of label in the various components of this fraction were determined. Stachyose, which contained the major portion of the label of this fraction, was hydrolyzed and the resultant hydrolysate was separated by paper chromatography. Specific activities of the hexoses derived from stachyose were determined. It was found that the glucose and fructose moieties of stachyose became labeled at the same rates; however, the galactose moiety became labeled more rapidly.