Hedges in Japanese conversation are discussed in relation to three social variables: age, sex, and formality. In the present study, hedges are defined as expressions of uncertainty, possibility, or tentativeness, all of which convey a sense of vagueness. I quantified the use of 26 Japanese hedges (e.g., toka ‘or something’, kana ‘I wonder’, nanka ‘like’, and tabun ‘probably’). Three hypotheses were posited to investigate the effect of the social variables: hedges are used (1) more often by younger speakers than by older speakers; (2) more often by women than by men; (3) more often in casual speech than in formal speech. Data of 20 single-sex dyads were collected from two age groups and from both sexes. The data supported hypotheses (1) and (2), but not (3). Most notably, younger female speakers use hedges often. Social factors of the speaker as well as context play an important role in the use of hedges in Japanese conversation.