A conceptualization and measure of argumentativeness is reported. Argumentativeness was conceptualized as a trait Which is composed of the tendency to approach arguments and the tendency to avoid arguments. A 20-item, self-report scale was developed in a series of three factor analytic studies. The internal consistency and test-retest reliabilities of the scale were high. A series of additional studies yielded considerable evidence as to the validity of the scale. The conceptualization of argumentativeness accounts for state as well as trait components. The state components consisted of the individual's perceptions of the probability and importance of success and failure in a particular argumentative situation. A hypothesis was supported which posited response to a particular argument would be predicted better by trait and state components together than by the trait component alone.