The objective of this study was to determine the tannin contents in the bark oftwenty-five species of Eucalyptus through two extraction methods, one using hot water andthe other a sequence of toluene and ethanol. The results showed that the extraction methodspresented significant differences in the tannin contents. The method using the sequencetoluene and ethanol, for most of the species, promoted a larger extraction of tannin. The hotwater method presented higher contents of tannin for Eucalyptus cloeziana (40,31%),Eucalyptus melanophoia (20,49%) and Eucalyptus paniculata (16,03%). In the toluene andethanol method the species with higher tannin content was Eucalyptus cloeziana (31,00%),Eucalyptus tereticornis (22,83%) and Eucalyptus paniculata (17,64%). The Eucalyptuscloeziana presented great potential as commercial source of tannin, independent of theextraction method considered.