OBJECTIVES: Discrepancies in diagnosis, treatment, or prognosis may emerge among physicians. a known decision-making bias is the tendency to shift personal opinion either toward or away from a previous opinion. We sought to evaluate such biases in the context of second-opinion medical consultations. METHODS: We distributed a survey questionnaire to a nationwide sample of orthopedic surgeons and neurologists. The questionnaires presented eight scenarios, each with conventional treatment options with no clear-cut preference. In four scenarios, the physicians were told that a previous opinion had already been given by another physician, or that a second opinion will be given, and the other four scenarios were used as controls. The physi-cians’ responses were coded according to the level of intervention (conservative to interventional). RESULTS: 172 orthopedic surgeons and 160 neurologists fi lled out the questionnaires, which represent about 50% of these specialties in Israel. In the orthopedic questionnaire, when a fi rst opinion had already been given, there was a shift toward a more interventionist treatment (P < 0.05). This was especially prominent when the fi rst opinion was known to the second physician. When the patient intended to seek a second opinion, there was a shift toward a more conservative treatment. No such effect was found among neurologists. CONCLUSIONS: Physicians’ judgment may be affected by another physician’s opinion (compared to their choices without a fi rst opinion). This bias mainly tends toward a more interventionist treatment. Due to the immense impact of any decision on patient health and resource use, further research should address such biases and develop tools to address them.