To estimate the number of deaths attributable to diabetes in 20–79-year-old adults in 2019. The following were used to estimate the number of deaths attributable to diabetes: all-cause mortality estimates from the World Health Organization life table, country level age- and sex-specific estimates of diabetes prevalence in 2019 and relative risks of death in people with diabetes compared to people without diabetes. An estimated 4.2 million deaths among 20–79-year-old adults are attributable to diabetes. Diabetes is estimated to contribute to 11.3% of deaths globally, ranging from 6.8% (lowest) in the Africa Region to 16.2% (highest) in the Middle East and North Africa. About half (46.2%) of the deaths attributable to diabetes occur in people under the age of 60 years. The Africa Region has the highest (73.1%) proportion of deaths attributable to diabetes in people under the age of 60 years, while the Europe Region has the lowest (31.4%). Diabetes is estimated to contribute to one in nine deaths among adults aged 20–79 years. Prevention of diabetes and its complications is essential, particularly in middle-income countries, where the current impact is estimated to be the largest. Contemporary data from diverse populations are needed to validate these estimates.