The objective of this population-based study was to determine whether traumatic experiences in general, and multiple traumatic experiences in particular, are associated with persistent self-rated depressive symptoms in adult Finnish subjects over 2 years of follow-up. The study sample included 1405 subjects aged 25-64 years. Subjects (n = 217) who were depressed both at baseline in 1999 and on follow-up 2 years later in 2001 (having persistent depressive symptoms) were compared with subjects (n = 987) having no depressive symptoms either at baseline or on follow-up. All six categories of traumatic experiences (wartime experience, natural disaster, life-threatening accident, victim of violent crime, domestic violence and childhood sexual abuse) pertained to the respondents' whole life span. Odds ratios, adjusted for significant covariates, were obtained from multiple logistic regression models that estimated the likelihood of persistent depressive symptoms in different trauma categories. Persistent depressive symptoms had a significant positive graded relationship with the number of traumatic experiences. The adjusted odds of persistent depression was 6.05 (95% CI 1.76-20.7) for men and 6.99 (95% CI 2.69-18.2) for women in those with three or more traumatic experiences compared with those with no such experiences at all. Multiple traumatic experiences substantially increase the likelihood of persistent depressive symptoms. Mental health intervention, as early as possible, may serve to prevent the chronicity of depressive reactions among victims of multiple traumas.