Experiencing conflictual relations with one's parents while growing up has been linked to onset, recurrence, and worse treatment outcome of adolescent depression. While this suggests that significant problems in the parent-youth relationship make depressive disorders more relentless, it is not clear whether this effect lasts into adulthood. Our aim was to examine if major and minor conflict with parents while growing up predicts depression in adulthood in youth with and without a history of depression. We utilized data from the Uppsala Longitudinal Adolescent Depression Study. This community-based cohort was assessed with structured diagnostic interviews both at age 16-17 and at follow-up 15 years later. The analyses included 382 individuals (227 with a history of child or adolescent depression; 155 peers without such a history). Binary logistic regression was used, adjusting for sex, disruptive behavior disorders, and additional family-related adversities. Among individuals with adolescent depression, major conflict with parents was strongly associated with adult depression (adjusted OR 2.28, 95% CI 1.07-4.87). While major conflict with parents was rare among non-depressed controls, a non-significant association of similar magnitude was still observed. Minor conflict, on the other hand, was not significantly associated with adult depression. Overall, conflict with parents did not predict adult anxiety disorders, substance use, suicidal behavior, somatoform disorders, or psychotic disorders. In conclusion, major parent-youth conflict during upbringing seems to be linked with an increased risk of depression in adulthood. These findings underscore the need to consider contextual/familial factors in the prevention and clinical management of early-life depression.