One of the ethical principles of medical research involving human subjects is obtaining proper informed consent (IC). However, if the participants’ actual awareness of medical research terminology is lower than the researchers’ prediction of that awareness, it may cause difficulty obtaining proper IC. Therefore, this study aims to clarify the presence of “perception gaps” and then discuss IC-related issues and measures based on the insights obtained. We conducted two online surveys: a “public survey” to understand the Japanese public’s awareness of (...) 11 medical research terms and a “physicians’ survey” to investigate physicians’ predictions regarding public awareness. In the “public survey,” for each term, respondents were instructed to select their situation from “understand,” “have heard,” or “have never heard.” In the “physicians’ survey,” respondents were asked to estimate the proportions of the general public who would “have understood,” “have heard,” or “have never heard” by using an 11-step scale. We analyzed separately in two age groups to understand the age-related difference. We received 1002 valid responses for the “public survey” and 275 for the “physicians’ survey.” Of the public respondents, more than 80% had never heard of terms such as interventional study, prospective clinical study, cohort study, Phase I clinical trial, or double-blind study. Concurrently, physicians overestimated general public awareness of the terms placebo, cohort study, double-blind study, and randomized clinical trial (in the group of people under 60). The results revealed the perception gap between the general public and physicians which raise serious concerns about obtaining proper IC from clinical research participants. (shrink)