Scanning tunneling microscopy offers the possibility of visualizing biological molecules in conditions similar to those in vivo with molecular resolution. Images of DNA and various proteins have been obtained, but insufficient conductivity through, and inhomogeneous and unstable adsorption of the biomolecules continue to prevent reliable imaging. Applying a metal coating to samples, to separate the conductivity and deposition problems has yielded satisfactory deposition procedures in various laboratories, but extension of this protocol to high resolution imaging of macromolecules has yet to be demonstrated. In this paper we present a review of the main results obtained in our laboratory, which illustrate the main problems encountered by investigators attempting to image metal-coated and uncoated biological specimens.