The purpose of this study was to create a new scale with a validated construct to measure professional identity development in students being prepared to become new practitioners. Using the new survey instrument (named the Professional Identity Five-Factor Scale), data were collected from a polytechnic with students enrolled in a wide range of professions. The confirmatory factor analysis found the construct valid and stable across independent samples from the same student population. When the sample was divided into two groups (high and low scores) based on the overall Professional Identity score, the stronger professional identity group scored significantly higher than the other group in all five factors. Our analysis also found the measure reliable using coefficient H as the indicator. Besides a new scale to measure, the underlying construct can also be used as a general guide or framework for the development and evaluation of professional education programmes.