Hospital clowns work worldwide as a health humanization resort, providing interplay with patients, family and staff. This type of activity varies greatly in terms of professionalism, accountability and artistic methods. Recently, some healthcare universities have introduced the clown language to undergraduates, aiming to train non-technical skills, often underrated in traditional healthcare teaching. Two 64-hour weekly hospital clown trainings were performed in a healthcare university in São Paulo, Brazil, in 2011 and 2012, with students from different undergraduate courses. The objective of this study was to assess the students' perceptions about this training. Subjects were asked to answer an open-ended question about their experience during the training. Answers were analyzed following the thematic analysis principles. Five theme categories were found: 1) expectations about the training; 2) perceptions of developed skills; 3) difficulties, doubts and unquietness; 4) influences on social and academic settings; 5) clown concepts after the training. Students highlighted improvement of listening, sustaining eye contact and dealing with failure as important apprehended concepts. The training process was considered deep and serious, and generated questioning and doubts in the subjects. Students reported influences on their daily activities, namely relationship improvement with family, friends and patients and enhanced of oral presentations. The clown training exhibited a potential for professional attitude construction and reflected on the students' lives, regarding development of interpersonal competencies.