Contribution: Increased understanding of the influence of a project-based multidisciplinary design and innovation course on students' engineering design thinking, specifically regarding problem framing. Background: Entrepreneurship-related education has been offered to engineering and technology students, but its influence has been discussed mainly in terms of students' self-efficacy or awareness of entrepreneurship or technological innovation, relying mostly on their self-reported data. Research Questions: 1) How do undergraduate students perceive the relationship between entrepreneurial mindsets and engineering design thinking after a project-based design course that integrates entrepreneurial activities and 2) How differently do they frame a design situation after this course? Methodology: This qualitative case study involved 14 undergraduate students pursuing a minor in design and innovation at a polytechnic institute. For more systematic data collection and analysis, a conceptual framework was developed based on literature about cognitive operations for problem framing and entrepreneurial engineering mindsets. Primary data were collected through semi-structured interviews and pre- and post-activities focused on problem framing. The interview and activity data were analyzed through multiple qualitative analysis approaches based on the conceptual framework. Findings: The analysis of the interview responses reveals the participants' thoughts on the role of an entrepreneurial mindset in engineering design practice, and the comparison between their pre- and post-problem framing activities shows that they tended to focus more on Customer and Social problem elements and less on Technical and Business problem elements after the course. However, important questions remain to better understand the impact of this change on their design abilities.