Human tooth agenesis involves the absence of one or more teeth and often refers to a genetic or a developmental disorder. Identifying whether certain patterns of tooth agenesis are more prevalent than others may prove valuable for treatment planning, as well as for genetic research into its etiology and development. In the present article a method is described where unique values are assigned to patterns of tooth agenesis. Using the idea of binary arithmetic, the absence or presence of teeth are represented by 1 and 0, and translated into corresponding unique values, the Tooth Agenesis Code (TAC). This procedure has an advantage over existing methods in that it allows for easier data analysis. The method described in this article can advance genetic research towards the etiology of tooth agenesis, allows researchers to communicate unequivocally the phenotypes of their studied cases and it can be used in other areas of oral pathology that also require pattern recognition.