Characteristic differences in sugar composition were shown to exist between various tissues of stem and roots of the tomato plant. Secondary xylem and the region of the internal phloem strands proved to be rich in sucrose, while glucose was the dominant sugar in the pith parenchyma. Moreover a gradual increase in the sucrose/glucose and starch/glucose ratios with increasing distance from the top of the stem was demonstrated for whole stem and root sections as well as for their component tissues. The relative amounts of xylem and pith in the stem on the one hand and the roots on the other partly explain the differences in sugar composition between these plant parts.