This project explored the impact of a research mentoring program on the development of graduate trainees' mentoring competencies. Graduate students participating in a research mentoring program completed the Mentoring Competency Assessment at the beginning and end of the program. Undergraduate students also provided an evaluation of their mentors' competencies. Results show that graduate students' perceptions of mentoring competencies increased from beginning to end of the program for 13 out of 26 competencies with mentors exhibiting moderate skill levels across all competencies as indicated by their self-report and undergraduate mentees' perceptions of their mentors' skills. These results provide support for the impact the research mentoring program has on graduate students' perceptions of mentoring competencies over time.