Osmotic adjustment was studied in 6-month-old seedlings ofEucalyptuscamaldulensisDehnh.,EucalyptustereticornisSmith,EucalyptusviminalisLabill., andEucalyptusgrandisHill ex Maiden. Because osmotic adjustment is related to water-stress tolerance, it can be used as a selection criterion of material adapted to drought. Half of the individuals of each species were submitted gradually to water stress, while the rest were maintained in soil at field capacity. Twenty-five days later the effect of stress on the development of osmotic adjustment was analyzed. All species had adjusted osmotically. The lowest osmotic adjustment was observed inE.camaldulensisandE.grandis(14.1% and 15.2%, respectively).EucalyptusviminalisandE.tereticornishad values of 32.3% and 41.9%, respectively. Our results demonstrate that species differ significantly in their extent of osmotic adjustment under drought stress, and that it is possible to use this inductive plant feature as one of the criteria to select, during early developmental stages,Eucalyptusgenotypes adapted to drought-prone environments. Some phylogenetic considerations are presented.