Subject of this article is the Belgian citizen's oppositional behaviour taken in the largest sense and considered as an opportunity to express his preferences. Starting from the supposition that a policy decision is not perceived as being conform to the citizens' interests or beliefs, attention is focused on their propensity to engage in oppositional action and their preferences for different means of expression.Such propensity appears to be rather limited and therefore one has also examined their belief in the success of an oppositional action and their insight in contemporary societal problems. Those data are compared with the actual oppositional behaviour during the last five years, which was found to be even smaller than the propensity. Further, three scales are constructed, indicating similarities and dissimilarities, as far as means of expression are concerned, between the preferences of the whole population and the behaviour of the small number of opponents. In a second approach, the degree of politica! participation, dissatisfaction and information is successively examined in relation to the oppositional behaviour. This research reveals that each of these three elements induces a more intensive oppositional activity as well as a different behaviour concerning the use of oppositional means. Political participation however is the most infiuencing factor. Oppositional behaviour is a complex phenomenon. Information on the content of the oppositional action, not included in this inquiry, would complete this approach.