This study examines student perceptions about (i) whether writing in undergraduate disciplines contributes to the development of student pre-professional identity (PPI) and (ii) how writing in such disciplines affects PPI relative to other classroom activities. The study was conducted at St. John's University in New York, which has a very diverse student population, and involved four different undergraduate disciplines--First-Year History, Chemistry (STEM), Legal Studies, and Speech Pathology. Data was derived primarily from student survey responses. Our findings suggest that writing in undergraduate courses can affect student PPI. Further, the extent to which writing contributes to PPI relative to other course activities appears to be related to four things: whether the course was in the student's major; how professionally authentic the students perceived the writing in the course to be relative to other course activities; the extent to which the instructor works through the disciplinary writing process with the students; and the extent to which the student already has a PPI.