OBJECTIVES: To compare the frequency of self-reported gaps in care coordination and self-reported preventable adverse events among adults with vs without diabetes. STUDY DESIGN: Cross-sectional analysis of REasons for Geographic And Racial Differences in Stroke (REGARDS) study participants 65 years and older who completed a survey on health care experiences in 2017-2018 (N = 5634). METHODS: We analyzed the association of diabetes with self-reported gaps in care coordination and with preventable adverse events. Gaps in care coordination were assessed using 8 validated questions. Four self-reported adverse events were studied (drug-drug interactions, repeat medical tests, emergency department visits, and hospitalizations). Respondents were asked if they thought these events could have been prevented with better communication among providers. RESULTS: Overall, 1724 (30.6%) participants had diabetes. Among participants with and without diabetes, 39.3% and 40.7%, respectively, reported any gap in care coordination. The adjusted prevalence ratio (aPR) for any gap in care coordination for participants with vs without diabetes was 0.97 (95% CI, 0.89-1.06). Any preventable adverse event was reported by 12.9% and 8.7% of participants with and without diabetes, respectively. The aPR for any preventable adverse event for participants with vs without diabetes was 1.22 (95% CI, 1.00-1.49). Among participants with and without diabetes, the aPRs for any preventable adverse event associated with any gap in care coordination were 1.53 (95% CI, 1.15-2.04) and 1.50 (95% CI, 1.21-1.88), respectively (P comparing aPRs = .922). CONCLUSIONS: Interventions to improve quality of care for patients with diabetes could incorporate patient-reported gaps in care coordination to aid in preventing adverse events.