Undergraduate research is a high-impact educational practice. However, few studies have analyzed the opportunities and barriers to entry into undergraduate research experiences. A survey for the measurement of undergraduate research science capital (URSC) was developed, rooted at the junction of science capital and social cognitive career theory. Respondents (n = 833) were science majors at four R1 institutions. Exploratory and confirmatory factor analysis confirmed a five-factor structure for the URSC scale. This study shares the development of the scale that can be used by science departments and their respective institutions to analyze the pathways to undergraduate research and consider what changes may increase equitable access to these experiences.