Scanning tunneling microscopy (STM) imaging of four nucleic acid bases, adenine, guanine, thymine, and cytosine, has been performed on the surface of SrTiO3single‐crystal substrates. The images indicate that the bases are deposited as individual molecules in ultrahigh vacuum condition, and can be individually observed by STM. A comparison of the heights and lateral dimensions of the deposited species and also the bias dependence of the heights, enables differentiation between four nucleic acid bases in real space.