The viscoelastic response of inhomogeneous rubbery blends upon interacting with an atomic force microscopy (AFM) cantilever is characterized in both the contact and intermittent contact states. In particular, loss tangent spectra and images are measured in tapping mode AFM at relatively high frequencies (>10(5) Hz) and in an AFM-based method in the contact state recently developed for the characterization of the viscoelasticity of soft materials in a frequency range of 10(0)10(4) Hz. Comparing the measured data to that from a bulk technique reveals that a combination of these two methods can qualitatively characterize the nanoscale viscoelastic behavior of inhomogeneous rubbers over an unprecedented frequency range. However, the loss tangent measured in the tapping mode is overestimated compared to those measured in the contact state and the bulk technique, which is attributed to the existence of the adhesion energy hysteresis during the approach and withdrawal of the tip from the sample in the tapping mode. Such an overestimation becomes less pronounced near the glass transition region of the materials.