Purpose: Professional program assessment is necessary in an accreditation process, in order to ensure educational quality and public accountability. One avenue of assessment is through an internship. The challenge is to determine how evidence from this indirect learning experience can aid in accreditation. The purpose of this paper is to describe the use of internship supervisor evaluation feedback within the accreditation process for a professional interior design degree program. Design/methodology/approach: In this study, internship assessment was provided by feedback from intern supervisors. Ten years of supervisor feedback were analyzed using descriptive statistics and a content analysis of supervisor comments. Findings: Two hundred forty-seven internship supervisor evaluation documents were analyzed. Overall, supervisors positively evaluated the performance of the intern as Good to Excellent. A majority of supervisors (91%) provided comments that were positive yet vague, as most could not differentiate between the intern and the intern's performance. Practical implications: This study links experiential learning to its evidence that can be used in an accreditation process. The challenges for educators in developing an assessment tool useful for accreditation evidence and to be shared by multiple program degree stakeholders are also described. Originality/value: Research on internships usually focuses on the student's viewpoint. This study is original in that it examines the use of internship supervisor's evidence in program accreditation.