Contact and tapping mode atomic force microscopy have been used to visualize the surface of cultured CV-1 kidney cells in aqueous medium. The height images obtained from living cells were comparable when using contact and tapping modes. In contrast, the corresponding, and simultaneously acquired, deflection images differed markedly. Whereas, as expected, deflection images enhanced the surface features in the contact mode, they revealed the presence of a filamentous network when using the tapping mode. This network became disorganized upon addition of cytochalasin, which strongly suggests that it corresponded to the submembraneous cytoskeleton. Examination of fixed cells further supported this assumption. These data show that, in addition to the structural information on the cell surface, the use of the tapping mode in liquid can also provide a good visualization of the membrane cytoskeleton. Tapping mode atomic force microscopy appears to be a promising technique for studying interactions between cell surface and subsurface structures, a critical step in many biological processes.