Aim: This paper presents the results of a pilot-study to assess mental stress in school teachers in the German state of Baden-Württemberg. Methods: Over 11 000 teachers working in nine different types of schools were interviewed with a semi-standardized questionnaire with 31 items arranged in four groups. The collective was dichotomized at the 95th percentile of the mean value and subjected to logistic regression analysis. Results: The response pattern differed in different types of schools, revealing more stress in secondary schools than in primary. Teachers working in Gymnasien (grammar schools) seem to feel the lowest emotional burden. Multivariate analysis reveals older age as a highly correlated (ORmax = 3.9) and female sex as a moderately correlated (OR = 1.3) risk factor for mental stress. Conclusions: Older female teachers at Hauptschulen (the least academic type of secondary school) show the highest cumulative risk of stress. The results indicate a necessity for measures to retain the endangered working capacity of older teachers. For routine screening of stress at work for teachers, a standardized questionnaire is necessary. Intervention has to be planned carefully and implemented at a defined threshold. Essential is the coordination of all stakeholders.