As the number of applications of carbon nanotubes (CNT) in the field of nanomedicine is growing quickly (imaging, drug delivery, scaffolds for tissue engineering), questions are raised about their potential toxicity. Because their annual production is now reaching hundreds of tons per year, their application in composite materials are becoming a reality. Dissemination in the environment could also happen during different steps of their life cycle, from their production to their processing, use and finally during disposal or recycling. We will review in this paper the state of the art in the field of toxicity and ecotoxicity of carbon nanotubes and try to highlight some recommendations.