This paper presents the findings of a large-scale nationwide investigation into stress among teachers in the UK, Data were collected via a questionnaire, from a random sample of 1790 teachers drawn from a cross-section of school types, sectors and teaching grades. Univariate analysis of the results revealed that teachers, as compared with other highly stressed occupational groups, experienced lower job satisfaction and poorer mental health. With regard to various subgroups in the sample, bivariate analysis revealed that it is necessary to consider the relationship between the level and nature of stress experienced and membership of a particular subgroup within the teaching profession (e.g. being a head teacher). Further examination of the data via the use of multivariate analysis revealed that ten reliable factors regarding 'sources of job pressure' could be obtained for this sample of teachers. Teachers were found to be reporting stress-related manifestations that were far higher than the population norms and of other comparable occupational groups. Multiple regression analysis was performed on the total sample and various subgroups, and it was discovered that the 'job pressure factors' of 'management/structure of the school' and 'lack of status and promotion' were the major predictors of job dissatisfaction. Mental ill-health was predicted by a variety of job pressure and personal factors, but predominantly linked to job pressure from 'ambiguity of the teacher's role'. Intention to leave was found to be most highly related to mental ill-health in teachers.