30 Background: While research has explored the role of companions (accompanying family members) in medical visits, studies have not examined companions’ involvement in pre-surgical visits. This study explored how companions’ presence impacts communication and satisfaction during pre-surgical visits to discuss major cancer surgery. Methods: Secondary analysis of 61 pre-surgical visit recordings with 8 surgical oncologists at an academic tertiary care hospital. Recordings were analyzed using the Roter Interaction Analysis System, and surgeons and patients completed a post-visit satisfaction questionnaire. Poisson and logistic regression models were used to assess differences in communication and satisfaction when companions were present (n = 46, 75%) and not present (n = 16, 25%). Models were fit using generalized estimating equations to account for nesting of patients within surgeons. Results: Companion communication was largely emotional and facilitative. In unadjusted analyses, companion presence was associated with a 29% increase in surgeon talk in the visit overall (IRR 1.29, p = 0.006), and a 41% increase in the amount of medical information provided (IRR 1.41, p = 0.001). Companion presence was associated with 45% less patient disclosure related to lifestyle/psychosocial topics (IRR 0.55, p = 0.037). In adjusted analyses, companions’ presence was associated with 23% lower levels of patient-centeredness (IRR 0.77, p 0.004). No difference between visits with and without companions in patient nor surgeon satisfaction. Conclusions: Companions’ presence increased the medical focus of the discussion; surgeons conveyed more medical information, and patients disclosed less psychosocial information. Companions might perceive patients as anxious prior to major surgery, compelling companions to advocate for the patient. Companion’s presence might be beneficial; however, this benefit might not be captured by the patient-centeredness ratio. As there was no difference in satisfaction, patient and surgeon satisfaction may not be predicated on patient-centeredness, but on the conveyance of timely, surgery-related information. Clinical trial information: NCT02489799.