This paper presents the findings of a mixed methods study regarding students' perceptions of mentoring in a cooperative education (co-op) program. Specifically, content analysis of student interviews suggested a lack of understanding of the mentoring process as characterized by unexamined assumptions and inadequate preparation for the co-op experience. It was noted that the STEM pipeline continues to shrink through decreasing student enrollment and increasing rates of retirement in industry. Cooperative education and internship programs can provide institutions and employers with a unique opportunity to recruit and retain students for a highly skilled and technically proficient workforce. This paper identifies key skill sets, knowledge and dispositions that undergraduate students in the STEM fields need to become successful proteges within a cooperative education or internship placement.