We conceptualize employment status not as a dichotomy of working versus not working but as a continuum ranging from adequate employment to inadequate employment (involuntary part-time or low wage) to unemployment. Will shifts from adequate to inadequate employment increase depression as do shifts from employment to unemployment, and to what extent does prior depression select workers into such adverse employment change? We analyze panel data from the National Longitudinal Survey of Youth for the years 1992-1994 for the 5,113 respondents who were adequately employed in 1992. Controlling for prior depression, both types of adverse employment change resulted in similar, significant increases in depression. These direct effects persisted despite inclusion of such potential mediators as changes in income, job satisfaction, and marital status. Marital status buffered the depressive effect of both types of adverse change, but education and job dissatisfaction amplified the effect of unemployment on depression. Prior depression did not predict higher risk of becoming inadequately employed but did predict increased risk of unemployment, particularly for those with less education. These results confirm that both unemployment and inadequate employment affect mental health, and they invite greater efforts to monitor the extent and impact of underemployment.