OBJECTIVES:  Insulins represented the largest proportion of costs of antidiabetic drugs in Poland. They are reimbursed in Poland, based on Heath Technology Assessment (HTA) recommendations and using reference pricing approach (RP). The aim of the study was to describe trends in insulins utilization pattern in Poland during 2012-2015 and to analyse factors influencing cost of insulins METHODS: National Health Fund database was used to extract data on cost and volume of insulins. Insulins were aggregated into groups by molecular origin and duration of action. Costs are reported in current international dollars, based on purchasing power parity (in 2015 1 USD=1,776 PLN), and include public payer and patient payment. Changes over time are presented using 2012 as a base. RESULTS: Between 2012-2015 both volume and costs of insulins increased by 22% (from 5.370.000 to 6.533.000 pack and from 356.707.000 USD to 436.645.000 USD), with higher rate of increase among analogues than human insulins (34% vs 14% by volume and 38% vs 10% by cost). The insulin volume was dominated by biphasic human insulins, but their share among insulins decreased from 36% to 31%. At the same time the share of short-acting analogues and human basal insulins increased from 29% and 15% to 31% and 19%, respectively. The main contributors to the increase in cost were analogues, while the increase in volume was related to short-acting analogues and human basal insulin. The rate of increase in volume and cost was highest among long-acting analogues (280%), reimbursed in Poland from 2012, but their share among insulins did not exceed 4% in volume and 8% in cost, mostly because restrictions implemented based on HTA recommendations. CONCLUSIONS: The study shows parallel increase in volume and costs of insulins. The changes in subgroups are in line with recommendations based on HTA and are influenced by RP.