To learn the prevalence of mood and anxiety disorders (as defined by the Diagnostic and Statistical Manual of Mental Disorders, Third Edition, Revised) in a working population in Japan, we analyzed data from a population-based survey. Among 140 respondents who had a job, 8% experience any of seven mood and anxiety disorders in the past 6 months and 19% had in their lifetime. The 6-month and lifetime prevalence rate of major depressive episodes were 4% and 14%, respectively. The 6-month and lifetime prevalence rates of phobic disorders were both 4%. The lifetime prevalence rates for other anxiety disorders were 1% or less. The 6-month rate of any disorder, as well as 6-month and lifetime rates of phobic disorders, was higher in white- collar employees than in self-employed workers (P < 0.05). The multiple logistic regression confirmed the tendency after controlling for sex and age, although the result was not significant (P > 0.05).