The communications of physician and patient vary with the characteristics of patient and consultation, as well as the communications of the counterpart. The purpose of this study is to explore the interaction between physician and patient communications in Japanese cancer consultation in view of the influence of patient and consultation characteristics. One hundred and forty cancer outpatients and 12 physicians were included in this study. The Roter Interaction Analysis System (RIAS) was used to analyze the physician-patient interaction. Patient information giving was positively related to physician facilitation, while patient question asking and emotional expression were associated with the warm and empathetic attitude of the physician. On the other hand, the encouraging statements of the physician were greater in shorter consultations, which implies physicians might have interrupted patients with encouragement before thoroughly listening to the patients concern. Further investigation is needed to confirm the causal relationships of these interactions.