Many textbooks indicate the desirability of using specific medical interview behaviors to obtain information from patients, although little evidence has been presented. The aim of this study is to investigate the relationships between the use of medical interview behaviors and the amount of information obtained. The behaviors studied included: open-ended questions, facilitation (comments or interviewer behavior that encourages the patient to continue talking), the open-to-closed cone (the gradual narrowing of focus from an initial nondirective approach to a more direct exploration), summarization (providing the patient with an explicit verbal summary of the information gathered thus far), and surveying problems. The subjects were 315 patients who visited an outpatient facility. These medical interviews were videotaped and reviewed by a trained rater using the Takemura Medical Interview Rating Scale, which was developed to assess the use of particular medical interview behaviors and to measure the amount of information obtained from patients regarding their chief physical complaints. Significant positive relationships were found between three particular interview behaviors and the amount of information obtained: facilitation, the open-to-closed cone, and summarization. These positive relationships were still present after adjusting for other medical interview behaviors used, and after adjusting for the time duration of the medical interviews (F = 15.3, p < 0.0001; F = 40.1, p < 0.0001; F = 5.57, p = 0.019, respectedly). This study reveals a positive relationship between three specific medical interview behaviors (facilitation, the open-to-closed cone, and summarization) and the amount of information obtained in a real clinical practice setting.