Diabetes mellitus is a common systemic metabolic disease associated with high healthcare costs. Type 2 diabetes is a problem worldwide and its doubling in the last 30 years is a fact. The occurrence of diabetes is positively correlated with the growing number of overweight and obesity patients. Currently, according to the International Diabetes Federation 2017, 415 million people have been diagnosed as adults with diabetes, and forecasts for 2040 state that there will be 642 million people with diabetes. An analysis of methods and costs of diabetes treatment in Poland was carried out in the years 2012–2015, which shows that we have a steady increase in expenditure on diabetes treatment in Poland. The presented studies concerned consumption and costs of therapies lowering blood glucose levels. The costs of drugs used to treat diabetes complications were not analyzed. It is known that the use of modern therapies (usually initially expensive) results in an improvement of patients’ health at a relatively higher initial cost. However, taking into account the distant effects, the economic calculus definitely shows the advantage of modern treatment over cheaper traditional therapies. Progress in medicine allows for personalization of treatment and selection of drugs for a specific target group; therefore,it is reasonable to make decisions on the reimbursement of new technologies, while maintaining precisely defined qualification criteria, which allows for a positive therapeutic and economic effect.