Diabetes Mellitus (DM) is a common chronic disease and a public health challenge worldwide. The present study aimed to analyze the trend in DM incidence, mortality, and mortality-to-incidence ratio (MIR) world over 30 years. The age-standardized DM incidence and mortality rates for both genders and different countries of the world from 1990 to 2019 were extracted from the Global Burden of Disease (GBD) study and the Human Development Index (HDI) was obtained for all countries from the United Nations Development Program (UNDP) database. The mean trends for the indicators for developing countries, developed countries, and all countries were evaluated using Generalized Estimating Equations (GEE) and the spline model. The estimates showed that the global mean trend of DM incidence from 1990 to 2019 followed an upward trend with an annual increase of 3.73 cases per 100,000 people. The global mean of DM mortality followed an upward trend with an annual increase of 0.43 cases until 2005 followed by a downward trend after this year with an annual decrease of 0.14 and the global mean MIR followed a downward trend during the same period with an annual decrease of 0.001 per 100,000 people. Besides, the mean incidence of DM in developing countries followed an upward trend similar to the trend in developed countries. Additionally, the mean mortality rate due to DM in developing countries increased with a slope of 0.62 until 2005 and then decreased with a slope of 0.02, and the mean MIR trend in the developed and developing countries showed a downward trend. Thus, developed countries followed a relatively faster decrease in MIR than developing countries.The data from the present study show the increased incidence of DM has made it one of the most important health concerns in the world, and if this issue is not addressed, this disease can cause more concerns for communities in the coming years. This being so, more DM prevention and control programs need to be put into practice.