An adequate approach to reducing school absenteeism should focus on medical absenteeism as this is the most prevalent form of school absenteeism. The objective of this study is to explore the health condition of pre-vocational secondary students with extensive medical absenteeism from a biopsychosocial perspective. Data were obtained from medical assessments and Strengths and Difficulties Questionnaires (SDQs) of students with medical absence above threshold criteria (i.e. reported sick four times in 12 school weeks or more than six consecutive school days) who were referred to a youth health care physician. The results showed that the students had a mean absence rate of 14% in 12 school weeks. Of all students, 43.5% had a diagnosed disease and 81.5% had problems such as physical complaints not yet diagnosed, psychosocial problems, lifestyle problems and sleeping difficulties. Four groups could be distinguished: 13.4% with a diagnosed disease and no problem, 30.1% with a diagnosed disease and a problem, 51.5% with a problem and no diagnosed disease and 5.1% without a diagnosed disease or problem. Significantly higher scores of the Total difficulties-scale on the SDQ were found (mean 10.5; SD 5.8) in the study group, compared to a reference group (mean 9.1; SD 4.9). In conclusion, this study shows that when using the aforementioned criteria for extensive medical absenteeism to intervene with the absence, students with a mean absence rate of 14% in 12 school weeks are identified. If there was a diag-Y. T. M. Vanneste et al. 112 nosed disease, it was accompanied by problems about twice as often. More than half of the students' absence was caused by problems rather than a disease. The great diversity of these problems calls for a personalized approach. A broad perspective, including medical expertise, is needed to distinguish between emerging mental and physical diseases, psychosocial and lifestyle problems.