This paper explores the relationship between non-standard types of employment and mental health. The analysis uses data on workers from the first seven waves of the British Household Panel Study, 1991-97. Four different types of non-standard employment (non-standard ontracts, places, times, and weekly hours of work) are analysed and the General Health Questionnaire (GHQ) index is used as the measure of mental health. We find evidence of only a modest effect of all types of flexible employment on the GHQ scores of men and women. Although the workers’ non-standard employment behaviour does not significantly vary with their endowments and unobserved inputs, population health heterogeneity may still have a critical effect on the observed changes in labour market behaviour. Finally, we find some significant effect of non-standard employment on mental health when the sample is stratified by age and education.