Three experiments investigated the relation between need for cognitive closure and persuasion. In the 1st study, Ss high on an individual-differences measure of need for closure were more resistant to persuasion by their low need-for-closure counterparts than vice versa. In the 2nd study, Ss in a noisy environment, assumed to instill a relatively high need for closure, were more resistant to persuasion than Ss in a quiet environment, but only in presence of an initial informational base for an opinion. In its absence, Ss in the noisy (vs. quiet) environment were less resistant to persuasion. The interaction between need for closure and informational base was replicated in the 3rd experiment reverting to the individual-differences measure of need for closure. The discussion considered implications of these findings for further persuasion phenomena. An essential part of the persuasion process is formation of a new judgment by the "persuadee" in response to the persuader's advocacy. If so, the process whereby all judgments are formed or modified may be expected to also underly various persuasion phenomena. This assumption is implicit in major recent models of attitude change (Chaiken, Liberman, & Eagly, 1989; Petty & Cacioppo, 1986). It suggests that individuals' reactions to persuasion depend both on their cognitive ability to make sense, and critically evaluate the persuasive messages, and their motivation to apply that ability toward the processing of message information. Features of ability and motivation also figure importantly in the theory of lay epistemics (Kruglanski, 1989, 1990b), concerned with processes governing subjective knowledge, that is, with formation and change of people's opinions and judgments. In the lay epistemic framework, an important ability-related element is topic-relevant information available and accessible to the individual (Higgins, King, & Mavin, 1982). Furthermore, an important motivational factor is the individual's need to have cognitive closure on a judgmental topic. How prior knowledge and need for closure combine to affect persuasion is the central issue explored in the present research. Our general assumption is that depending on prior information, need for closure may differently impact individuals' mode of information processing and that this, in turn, may affect their reactions to persuasion. The need for closure has been described as "the desire for a