This article analyzes the interactions through which primary-care nurses and patients accomplish patient weighing. The analysis is based on videotaped nurse-adult patient interactions in clinics in the area of Southern California. Detailed examination of co-participants' naturally situated weighing conduct shows that parties recurrently deliver utterances that go beyond that required to accomplish weight measurement-precisely "where" they "are" within the weighing process shaping how they produce and understand these utterances. Using weighing as a locus of epistemic negotiation and potential affiliation, co-participants interactionally achieve the distribution of weight/weighing knowledge and the character of their social relationship. Confronting their numerical weight results in a social/medical setting, patients can use expansive weighing utterances to claim or demonstrate that they possess pre-existing knowledge regarding weight, asserting independent expertise vis-à-vis nurses and claiming result co-recipiency and co-ownership. Speakers can also use expansive utterances to proffer an interactional opportunity for affiliation, inviting recipients to collaborate in producing a more personalized encounter. Through the acceptance or declination of these invitations, the parties work out "who" they "are" to and for one another.