Background: The aim of the study was to assess mortality and years of life lost from diabetes mellitus in Poland between 2000 and 2022. Methods: The database was created from death cards made available for the purposes of this study by Statistics Poland. The study used data on deaths caused by type 1 diabetes mellitus, T1DM (N = 33,328), and type 2 diabetes mellitus, T2DM (N = 113,706). Standardized death rates (SDRs) and standard expected years of life lost per person (SEYLLp) and per death (SEYLLd) were calculated. A time trend analysis was performed using joinpoint models. The annual percentage change (APC) and the average annual percentage change (AAPC) were estimated. Results: Between 2000 and 2022, 33,328 people died from T1DM in Poland. The SDR rate increased from 6.0 to 8.8 per 100,000 population in the analyzed period. The APC was 1.3% (p < 0.05). SEYLLp rates per 100,000 population were 79.3 in 2000 and 109.2 in 2022. SEYLLd rates were 22.9 and 17.9 years, respectively (APC = −1.0%, p < 0.05). The mean age of those who died from T1DM increased from 66.1 in 2000 to 72.5 in 2022. Between 2000 and 2022, 113,706 people died from T2DM. The SDR increased from 12.5 to 37.7 per 100,00 (APC = 5.5%, p < 0.05). SEYLLp rates were 88.8 and 296.0 per 100,000 population (APC = 6.4%, p < 0.05). SEYLLd rates decreased from 16.9 in 2000 to 13.4 in 2022 (AAPC = −1.0%, p < 0.05). The mean age of those who died from T2DM increased from 73.1 to 78.1 years. Conclusions: The study showed a growing problem of diabetes as a cause of death and years of life lost.