The purpose of this study was to examine the scientifically gifted middle school students’ cognitive developmental levels, awareness and cognitive structures about scientific inquiry process. Twentyone cientifically gifted middle school students were given the Group Assessment of Logical Thinking test and the questionnaire which asked their awareness about 33 basic concepts of scientific inquiry process. To examine their cognitive structures, they were given those concepts and required to organize their own concept maps about scientific inquiry process. Results showed that three students were at the transitional period and 18 students were in the formal operational stage. For the concepts of tentative answer, independent variable, dependent variable, experimental group, control group, and hypothesis testing, most students answered that they had not heard about those concepts before or that they scarcely knew about them that they had heard about. Analysis of students’ concept maps showed that the students could not make propositions with unfamiliar concepts such as independent variables, dependent variables, control variables, hypothesis rejection and hypothesis support. Even worse, they made wrong propositions with familiar concepts such as hypothesis, prediction, and data organization. They did not know the difference between hypothesis and prediction or the relationship between inquiry process and data organization and interpretation.