- Second medical opinions have become commonplace and even mandatory in some health-care systems, as variations in diagnosis, treatment or prognosis may emerge among physicians. To evaluate whether physicians' judgment is affected by another medical opinion given to a patient. Orthopedic surgeons and neurologists filled out questionnaires presenting eight hypothetical clinical scenarios with suggested treatments. One group of physicians (in each specialty) was told what the other physician's opinion was (study group), and the other group was not told what it was (control group). A convenience sample of 332 physicians in Israel: 172 orthopedic surgeons (45.9% of their population) and 160 neurologists (64.0% of their population). Scoring was by choice of less or more interventional treatment in the scenarios. We used χ(2) tests and repeated measures ANOVA to compare these scores between the two groups. We also fitted a cumulative ordinal regression to account for the dependence within each physician's responses. Orthopedic surgeons in the study group chose a more interventionist treatment when the other physician suggested an intervention than those in the control group [F (1, 170) = 4.6, p = 0.03; OR = 1.437, 95% CI 1.115-1.852]. Evaluating this effect separately in each scenario showed that in four out of the eight scenarios, they chose a more interventional treatment when the other physician suggested an intervention (scenario 1, p = 0.039; scenario 2, p < 0.001; scenario 3, p = 0.033; scenario 6, p < 0.001). These effects were insignificant among the neurologists [F (1,158) = 0.44, p = 0.51; OR = 1.087, 95% CI 0.811-1.458]. In both specialties there were no differences in responses by level of clinical experience [orthopedic surgeons: F (2, 166) = 0.752, p = 0.473; neurologists: F (2,154) = 1.951, p = 0.146]. The exploratory survey showed that in some cases physicians' judgments may be affected by other physicians' opinions, but unaffected in other cases. Weighing previous opinions may yield a more informed clinical decision, yet physicians may be unintentionally influenced by previous opinions. Second opinion has the potential to improve the clinical decision-making processes, and mechanisms are needed to reconcile discrepant opinions.