This article presents the notion of symbiosis and how it changes the principles of conception and evaluation to insure the acceptance of technology. It is important to understand these new symbiotic technologies, in particular how they introduce new types of interaction and suggest new principles for human-computer interaction ergonomy. We first present a review of the literature and the main concepts that have been developed to gain a better understanding of acceptance, such as the TAM model (usability and usefulness), user satisfaction, and expectation and disconfirmation of expectations. The notion of symbiotic technology is then presented in relation to the critical capacity of the system to really complement and augment human information processing. Examples of symbiotic technologies are given, together with the principles which underlie their success and make up the ergonomic guidelines for symbiotic computer systems. New ergonomic criteria are proposed to ensure efficient symbiotic computer interactions?: amplification of intelligence, augmentation of perception, multiplier operative efficiency, adaptation of knowledge in context, balancing emotional, resilience in the management of errors, reduction of the distracters, and continuity of information flow. Their consequences are discussed from an ergonomical point of view.