To describe differences in post-traumatic stress (PTS) symptoms over time among racial and ethnic minoritized breast cancer survivors (BCS) with comorbid diabetes. In a multisite longitudinal study, post-traumatic stress was evaluated at baseline, 6 and 12 months through self-reported questionnaires (Impact of Events Scale-Revised [IES-R]). One hundred and seventy-eight post-treatment BCS with diabetes were recruited from three tertiary medical centers. Relative to non-Hispanic White women, minoritized women reported higher total IES-R scores at all time points. In the adjusted model, Latina women reported persistently higher IES-R total scores and Latina, and 'Other' women reported higher avoidance scores. Minoritized BCS with comorbid diabetes report higher rates of cancer related PTS that persist over 12 months. Post diagnosis PTS evaluation and support is important in survivorship and primary care practices. Linkage to socially and culturally sensitive community support may be warranted. [ABSTRACT FROM AUTHOR]