In the context of the Bologna reform, the Environmental Sciences programme at ETH Zurich was transformed from a Diploma to a Master's degree programme. In a comparative secondary analysis of graduate surveys of the last homogeneous cohort of Diploma graduates (N = 85) and two Master's cohorts after the reform (N = 108), this study investigated the qualifications required by graduates in their professional activities and matched them with the level of qualification acquired at university. It concluded that graduates' general skills meet professional requirements better after the reform. However, for two out of five domain-specific skills (knowledge of legal aspects, interdisciplinary knowledge) ratings of skill acquisition declined significantly. Nonetheless, Master's graduates showed a slight or substantial knowledge and skills advantage for seven of the eight skills of the programme's qualification profile that were addressed in the survey. The basic quality of the sustainability oriented programme has thus been maintained.