We used health care claims data to investigate trends in total health care spending on individuals with type 1 diabetes between 2012 and 2016. We found a rapid increase in total health care spending, driven primarily by gross spending on insulin that doubled over the period. During that time insulin use rose only modestly. While the composition of insulins used shifted, the price of all types of insulin and insulin products increased, with point-of-sale prices roughly doubling on average between 2012 and 2016. We conclude that increases in insulin spending were primarily driven by increases in insulin prices, and to a lesser extent, a shift towards use of more expensive products.