To investigate the association between country incidence of type 1 diabetes and mortality from infectious disease and antibiotic susceptibility. An ecological study to explore the relationship at a country level of the reported incidence of type 1 diabetes (DiaMond) to infectious disease mortality (World Health Organisation) and to antibiotic susceptibility (Alexander Project). There were significant negative correlations between the incidence of type 1 diabetes and mortality for all infectious diseases studied. There were also significant positive correlations between the incidence of type 1 diabetes and antibiotic susceptibilities of Strep. pneumoniae, but not to those of Haem. influenzae. Since infectious disease mortality and antibiotic susceptibility are surrogate markers for bacterial exposure, our results provide support for a negative association between bacterial exposure in a community and its incidence of type 1 diabetes. The consistency of our results as well as the highly statistically significant results of most of the associations studied reinforces the validity of our findings.