OBJECTIVE: To estimate diabetes-related deaths among Brazilian adults between 1999 and 2003 and to investigate demographic factors associated with reporting diabetes as an associated cause of death. METHODS: All deaths with diabetes as the underlying or associated cause were identified using the Brazilian Mortality Data System. Analysis was performed by sex, age, year, state of residence, and place of death. Mortality rates were age standardized by the 2000 Brazilian population. FINDINGS: A total of 237 946 deaths (8.8%) were related to diabetes; in 4.2% of deaths it was the underlying cause and in 4.6% it was an associated cause. Between 1999 and 2003, age-standardized mortality rates for diabetes as the underlying cause increased 14% among males and 9% among females, while mortality with diabetes as an associated cause increased 22% and 28%, respectively. Diabetes appeared more often as an associated cause in death certificates among older individuals and in those residing in São Paulo State; it appeared less often as an associated cause among women, brown- and black-skinned populations, and in deaths occurring outside hospitals. Cardiovascular diseases accounted for 54.5% of the underlying causes of death when diabetes was an associated cause. CONCLUSION: Diabetes was related to almost 9% of the deaths in the South and Southeast regions of Brazil. Mortality from diabetes is increasing, especially deaths with diabetes as an associated cause. The probability of having diabetes as the underlying cause of death is greater among women and nonwhite individuals. Our results reinforce the importance of using multiple causes of death to monitor diabetes, because half the individuals with the disease will die of another cause, especially cardiovascular diseases.