To determine the effect of treatment for Strongyloides stercoralis infection on type 2 diabetes mellitus in an Australian Aboriginal population.A three-year cohort study of 259 Aboriginal adults living in northern Australia. Subjects were tested for S. stercoralis infection, diabetic status and HbA1c at recruitment. 92 subjects were ELISA positive for S. stercoralis and 91 were treated with two doses of ivermectin 0.2mg/kg. Serological cure was assessed after 6months and those who remained positive were retreated. All subjects then underwent the same testing at 3years follow up.Follow up was successful in 80% of subjects. Eight new cases of T2DM were recorded, 7 in the treatment group and 1 in the non-treatment group (Unadjusted RR 7.71, CI 0.98–60.48, p=0.052. Adjusted RR 5.45, CI 075–35.92, p=0.093). In addition, worsening glycemic control (T2DM or newly diagnosed glucose intolerance) was recorded in 13 cases (10 treatment group, 3 non treatment. Adjusted RR 3.74, CI 1.06–13.20, p=0.04). There was a significant improvement in glycemic control in the patients with pre-existing T2DM when treated for S. stercoralis compared to the non-treatment group (Diff. −1.03, p=0.009).This study demonstrated a differential effect of treatment for S. stercoralis on glucose metabolism in patients with and without T2DM. It showed a significant effect on the development of T2DM and glucose intolerance in those without T2DM, while improving glycemic control in subjects with pre-existing T2DM. Although numbers in this study are small, it suggests that larger studies may be of interest.