This paper presents a hypothesis of the aetiology of the increasing incidence of type 1 diabetes (T1D). This together with the global increased incidence of celiac disease (CD) and that these increases cannot be explained by genetic factors suggest a common environmental factor for these two diseases. Even though enterovirus (EV) infections are believed to trigger T1D and gluten is the trigger of CD, the increasing intake of gluten containing products all over the world could be the trigger for both diseases directly and indirectly. It has been shown that the duration of exposure to gluten is related to the prevalence of T1D. It has also been shown that T1D patients at onset have an inflammatory reaction in the gut. Hence, early diagnose of CD followed by elimination of dietary gluten will lead to a decreased incidence of T1D.