The self-assembly of nucleobases adsorbed on a surface is the result of a delicate balance between intermolecular and adsorbate-substrate interactions. This process is thought to have contributed to the emergence of genetic coding and therefore the origin of life. In this study, scanning tunneling microscopy (STM) was conducted on cytosine monolayers formed on an inert Au(III) surface. Ultrahigh vacuum (UHV) and low temperature conditions were used to maintain a clean surface and stabilize the supramolecular network. At coverages below one monolayer, cytosine was observed to form a random network. The STM images obtained of cytosine on Au(III) will serve as a useful reference for future studies of the coadsorption of the base pairs cytosine and guanine as well as studies conducted using a chemically active substrate.