This study investigated risk factors of depression in fathers at 4 weeks post-partum using a cross-sectional design. Mothers were recruited at the 4 week postnatal health check between March and July 2007. A total of 510 mothers agreed to participate in the study. One-hundred-and-fifty-six fathers and 181 mothers returned the questionnaires. The Edinburgh Postnatal Depression Scale and the Center for Epidemiologic Studies Depression Scale were filled out to assess depressive symptoms. There was no association between paternal and maternal depression. According to the logistic regression analysis, paternal depression was associated with employment status, history of psychiatric treatment, and unintended pregnancy. Of eight fathers with unstable employment, seven were temporary employees and one was unemployed, suggesting that perinatal care-providers should independently screen for depression in fathers and mothers and focus attention on paternal employment status, especially temporary employment.