OBJECTIVE-To examine state differences in the reporting of diabetes-related incorrect cause-of-death (COD) causal sequences on death certificates in the U.S.RESEARCH DESIGN AND METHODS-We conducted a cross-sectional descriptive study to determine the prevalence of two types of incorrect COD causal sequences with data from the Multiple Cause Mortality File of the year 2004.RESULTS Among deaths in which diabetes was reported as the first diagnosis on line a, b, c, or d in Part I of the death certificate in the U.S., 21% had below diabetes placement error (ranged from 30% in Maryland to 7% in Hawaii) and 11% had above diabetes placement error (ranged from 18% in Kentucky to 5% in California). The net effects of the two types of error ranged from -0.7% in Nevada to 19.6% in the District of Columbia.CONCLUSIONS-Because the rates of incorrect reporting of diabetes-related COD causal sequence varied across states, the comparability of the diabetes death rate between states may have been compromised. Diabetes Care 35:1572-1574, 2012