The effect of long branching on the deformational behavior has been examined for four commercial high cis-polybutadienes with particular interest as to its implication on their processability. The techniques used were oscillatory shear measurements at small deformation and tensile stress-strain measurements at large deformation. In the shear measurements (linear behavior), the temperature dependence of the shift factor in the timetemperature superposition is related to the degree of branching obtained from dilute solution viscosity. In the tensile measurements (nonlinear behavior), the rubbers showed either strain-hardening or strain-softening. The difference was not related to the degree of branching determined by dilute solution viscosities. This means that the dilute solution viscosity is not an adequate means to explain the processability difference of the rubbers. The branch length, although the absolute value is unknown, is characterized as short or long on the basis of the strain-softening or strain-hardening behavior. Both small shear and large elongational measurements are necessary for characterization of branching pattern and processability. Rubbers with relatively short branches (strain-softening type) or with the smallest amount of long-branching (non-strain-hardening type) were found to straincrystallize most easily. The absence of strong resistance to stretching is the apparent reason for the ease of crystallization.