A sudden increase in the number of children with newly diagnosed type 1 diabetes mellitus (T1DM) was experienced during the third wave of COVID-19 epidemic in Hungary. The newly diagnosed T1DM patients had a significantly higher rate of anti-SARS-CoV-2 positivity as compared to prevalent T1DM children [OR (95% CI) 3.74 (1,08,13.55); P=0.04]. The relationship between SARS-CoV-2 infection and diabetes needs to be investigated further.