Abstract: Humans and other animals rely on familiarity with common sensory cues in the environment to guide behavior, while adapting to behaviorally relevant changing conditions. To support this adaptive behavior, sensory brain circuits balance competing needs for maintaining a stable and coherent representation of the external environment, while reorganizing in response following salient experiences. In the auditory cortex, neurons exhibit robust, consistent and selective responses to sound stimuli. On the other hand, experience can cause changes in the response properties of individual auditory cortical neurons as well as in the large-scale functional organization of the auditory cortex. However, little is known about the degree of longitudinal ensemble-level stability or plasticity of auditory cortical sound representations. To address this gap, we carried out longitudinal two-photon calcium imaging in the auditory cortex of awake mice to derive the response properties of identified neuronal ensembles to simple and complex sounds across days. Our preliminary results suggest a surprising degree of plasticity of sound-evoked responses within local neuronal ensembles in the auditory cortex.