This study tests a model that proposes that design elements of the e-store create environmental atmospheric that induce certain emotional states in the consumer, which in turn affect his/her attitudes towards the store. The model is based on concepts from the human-computer interaction (HCI) literature and on the environmental psychology model of Mehrabian and Russell (1974). The atmospherics of the e-store is captured in our model by perceptions of two design dimensions: usability and aesthetics. The results support the model propositions by showing a significant effect of site atmospherics on the emotions experienced during the shopping episode and, consequently, on attitudes towards the store. The study contributes to the development of a richer and more adequate model of consumer behavior in online shopping, by merging HCI and marketing theories, and by taking into account the effects of design on emotions.