This project is a revised taxonomic treatment of the tobacco genus, Nicotiana, for the Arizona Flora. The treatment required morphological descriptions of all six species found in Arizona based on measurements and observations from mounted herbarium specimen as well as field collections. Loans from regional herbaria including: Northern Arizona University, Arizona State University, the University of Arizona, Rancho Santa Anna Herbarium, and the Desert Botanical Garden were examined and annotated according to standard herbaria protocols. A dichotomous key was then created based on morphological descriptions for use in identifying species both in the field and from herbarium mounts. Distribution maps were generated using online databases of herbarium vouchers, mapping soft wares, and field excursions. During the course of my field work, I was able to locate all six species and four of them were collected, vouchered, and deposited in the ASU Vascular Plant Herbarium. One species, Nicotiana quadrivalvis was not relocated based on historical records. This treatment will contribute to ongoing revisions of the Arizona Flora via a publication in the regional taxonomic journal Canotia.