{Reference Type}: Case Reports {Title}: The Relationship Between COVID-19 and the Development of Diabetic Ketoacidosis and New-Onset Type 1 Diabetes Mellitus. {Author}: Kellogg C;Haenel LC; {Journal}: Cureus {Volume}: 16 {Issue}: 5 {Year}: 2024 May 暂无{DOI}: 10.7759/cureus.60711 {Abstract}: The COVID-19 pandemic with the outbreak of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus has been one of the largest topics of discussion in the medical world over the last few years. Most of the research has focused on the risks and correlation of chronic diseases and immunosuppression with the severity and mortality of the viral infection. Less research has occurred in the setting of post-infectious sequelae and the long-term effects of COVID-19 with the development of chronic conditions and diseases, such as new-onset type 1 diabetes mellitus. The incidence of diabetic ketoacidosis (DKA) has increased during the COVID-19 pandemic, but the relationship between the two conditions remains to be fully understood. We report the case of a 24-year-old male who presents with malaise, polyuria, polydipsia, headache, and fatigue and was eventually found to be in diabetic ketoacidosis (DKA). He had a history of COVID-19 infection 12 weeks prior to this presentation. He also had a family history of DKA and type 1 diabetes mellitus. This case highlights the need to perform an in-depth workup for each patient with DKA and new-onset diabetes mellitus in order to find a potential cause of the autoimmune condition.