It has been suggested that engineering research is advanced by an increasingly diverse population of Science, Technology, Engineering, and Mathematics (STEM) researchers with interdisciplinary research objectives. To develop a diverse population of STEM researchers, we must understand how their identities influence their feelings of preparedness for research experiences. The purpose of this study was to understand how a student's perception of preparedness is influenced by the student's science and engineering identity and his/her participation in interdisciplinary research. Underrepresented minority science and engineering undergraduate students participated in a National Science Foundation: Emerging Frontiers in Research and Innovation - Research Experience and Mentoring (REM) program for 1 semester. At the end of this research experience, students (n=10) were given an identity "pre-survey". A follow-up identity "post-survey" was given the first week of fall semester following various summer activities in which students participated. Domain-specific interest survey items revealed significant differences between science and engineering majors when the topic was engineering, for both pre-survey and post-survey responses. Results also indicate that both engineering and science majors are relatively confident in their level of preparedness for future research, signified by means above 6.0 for nearly every preparedness item. Before the summer experience, science students perceived significantly higher (p = 0.0039) recognition from their mentor(s) as compared to engineering students, whereas in every other aspect of science identity there were no significant differences by major in either pre- or post-summer experience items. The results suggest that early-stage engineering students identify less with research compared to their science counterparts and, subsequently, feel less prepared to conduct research; however, participation in an interdisciplinary experience increases their indication of academic research preparedness. The results show for, the population studied, that participation in a research program, such as REM and summer Research Experiences for Undergraduates, increases minority students' research identity, which may assist in increasing diversity of the STEM research population.