Effects of gibberellic acid (1 and 10 μg/plant) on internode extension and cell activity in Eucalyptus camaldulensis seedlings varied with internode position. The relatively small increased extension of lower internodes resulted from cell elongation whereas the progressively increasing growth in upper internodes was caused primarily by cell division. Transverse cell divisions induced by gibberellic acid seemed to require an active apical meristem. Changes in internode diameter growth (increased in lower internodes, decreased in upper) due to gibberellic acid were the result of changes in cell division. The major response to gibberellic acid seems to be an increase in transverse cell divisions and does not seem to be due to competition between meristems for the available food reserves. Copyright © 1969, Wiley Blackwell. All rights reserved