The incompatibility properties of two tumor-inducing (Ti) and seven tartrate (Tr) plasmids, derived from variousAgrobacterium vitisstrains, were characterized usingincRh1,incRh2,incRh3, andincRh4 clones which were established for the identification and classification ofAgrobacteriumplasmids. The testedA. vitisplasmids could be allocated into four groups on the basis of their incompatibility withincRh1,incRh2, andincRh4 clones. The two octopine tumor-inducing plasmids, pTiAT6 and pTiAB3, expressed incompatibility both toincRh1 and toincRh2 clones. Three pTrs could not be allocated either toincRh1-4 andincAg1 or to the wide-host-rangeincP1,incQ, andincW groups.