Carbon nanotubes (CNTs) have interesting chemical and physical properties. Since their discovery in the early 1990s, the structure and applications of CNT have been studied. The application of CNT, which we will focus on, is the development of sensors for detecting analytes in food. In order to have a better understanding of how and where to use CNT, a brief review is given. The topics include the description of types, structure, and synthesis of CNT and the characterization methods of CNTs that are most employed today, such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy, and Raman spectroscopy. We also present some biosensors that have been developed with CNT for the food industry.