The ability to discern chemical cues from the environment is vital for the survival of many animals. In the wild, animals must seek out high quality food sources and at the same time avoid naturally occurring toxins, constantly challenging their taste system. Little is known about the function of the gustatory system at the molecular level such as ligand binding, signaling, and central processing. While studies have analyzed the nature of taste perception, there is limited knowledge regarding the basic principles underlying taste reception. How are chemical cues converted into electrical impulses? How is gustatory information encoded? How does central processing of gustatory input lead to appropriate behaviors? Before one can begin to address these questions, a basic understanding of the functional organization of the taste system is necessary. Drosophila melanogaster has been used for many years to analyze the gustatory system because of its neuronal simplicity and ease of genetic analysis. Very little has been known about the organization of the taste system at both the neuronal and molecular levels. This work aims to elucidate basic principles of taste system function and organization. Here I describe an electrophysiological analysis of taste coding in the fly labellum, the main gustatory organ. To gain a better understanding of the functional organization of the gustatory system I utilized a large taste panel of taste compounds to define the function of all the taste sensilla on the labellum and analyzed their specificities. Included in this functional characterization, I show, for the first time, responses to amino acids in Drosophila and responses from taste peg sensilla. From this analysis we have derived conclusions about the functional organization of the taste system, and helped elucidate basic underlying principles of taste coding.