The present study focused on identifying the independent and conjoint influence of attitude similarity and initial interaction on interpersonal attraction to relative strangers. Participants were informed they would be working on a project with either an attitudinally similar or an attitudinally dissimilar stranger. Half of the participants next engaged in an initial interaction with their partner and the other half did not. All participants then filled out a scale that included a measure of interpersonal attraction. Results indicated that the conjoint, nonadditive effects of attitude similarity and initial interaction overrode the significant main effects of these variables. Although attitudinally similar noninteractants were more attracted to their partners than dissimilar noninteractants, no differences in attraction were observed among similar and dissimilar interactants. Dissimilar interactants were more attracted to their partners than dissimilar noninteractants, but no differences in attraction were observed between similar interactanls and noninteractants.