Objectives: The aim of this study is to analyze the epidemiological characteristics and the biological profile of children from the southeast of Romania who have been newly diagnosed with type 1 diabetes (T1DM) and to investigate the potential relationships between vitamin D deficiency and the onset of this disease, especially in the context of the COVID-19 pandemic. Methods: This is a retrospective study that included 79 children under the age of 18 who were diagnosed with T1DM at the St. Ioan Galati Children’s Emergency Clinical Hospital between 2018 and 2023. Their demographic data (age, sex, and home environment), medical history (family medical history, birth weight, Apgar score, and type of nutrition), and biological parameters, including glycemia, HbA1C, and vitamin D level, were collected. We used advanced statistical methods to compare the levels of vitamin D in the children with T1DM with a control group of nondiabetic children. Results: The demographic characteristics of new T1DM are a median age of 9 and female/male sex ratio of 1:3, with 50.6% living in urban areas, 59.5% with a normal body mass index, and 74.6% presenting with ketoacidosis. Vitamin D deficiency was found in 52% of diabetic cases compared to 2.53% in the nondiabetic controls. Conclusions: There is an increasing incidence of pediatric T1DM. Diabetic ketoacidosis was frequently diagnosed as an initial manifestation and has frequently accompanied lower levels of vitamin D. Children with T1DM showed significant vitamin D deficiencies compared to the control group, highlighting the need for the monitoring and supplementation of this vitamin.