Spanish Abstract: Las incertidumbres cientificas y el surgimiento de efectos no deseados han aumentado el clima de tension entre los diferentes agentes interesados o afectados por las decisiones tomadas en asuntos de ciencia y tecnologia. El rechazo o no aceptacion de las politicas publicas que se desprenden de estas decisiones obliga a cambiar los modelos tradicionales de gobierno en asuntos de evaluacion, control y gestion de riesgos. English Abstract: Scientific uncertainty and emerging non desired effects are increasing the tensions between the different agents interested or affected by decisions taken on scientific and technology issues. Rejection or non acceptance of public policies derived from these decisions force to change traditional government models on risk evaluation, management and control. This paper – part of a larger research on problems associated with risk – discusses the elements that increases tensions such as distrust between experts and non-experts, fear as a risk perception factor, and objective or subjective risk evaluation. In other hand, the different governance models are criticized, and finally, a model is proposed to permit an effective risk management and control.