Objective The number of women with screen-detected breast cancer is increasing, but it is not clear if these women experience the same levels of distress as women with symptomatic breast cancer. The current study compared stress and distress in women with screen-detected or symptomatic breast cancer at diagnosis and 12 months post-diagnosis.Methods Ninety-two women with screen-detected breast cancer and 129 women with symptomatic breast cancer completed measures of perceived stress, anxiety, and depression at diagnosis and 12 months post-diagnosis. Women also completed a measure of cancer-related stress 12 months post-diagnosis.Results Both groups reported similar levels of perceived stress, anxiety, and depression at diagnosis. A third of women in both groups reported clinical levels of anxiety at diagnosis, which decreased over time. There were no differences in depression. Analyses revealed that at 12 months post-diagnosis, the symptomatic group reported a significant reduction in anxiety, but the screen-detected group reported a nonsignificant trend for a reduction over time. The screen-detected group reported significantly higher cancer-related stress at 12 months than the symptomatic group.Conclusions Screen-detected women report similar distress at diagnosis but may be more at risk for greater distress requiring further psychological support 1 year after diagnosis. Future interventions that focus on preparation for screening may help to reduce ongoing levels of anxiety and cancer-related stress for this group.