Animal behavior, anatomy and physiology can vary significantly among genetically identical individuals. The majority of behavioral studies were conducted at a group level, and only the mean behavior of all individuals was considered.Similarly, in neuronal studies, data were pooled and normalized from several individuals. Nevertheless, individuality is an important aspect of behavior that should not be ignored. Recent studies have shown that behavioural biases and preferences can vary significantly among individuals of the same genotype. Here, we show that a highly inbred Drosophila laboratory strain (CS) stimulated with either aversive or attractive odors exhibit idiosyncratic odor preferences that persist across tests and days. Furthermore, we are currently investigating whether individual odor preferences are reflected by distinct odor response patterns in the fly brain to elucidate the neuronal mechanisms underlying individual odor-guided decisions.