OBJECTIVES: Existing evidences indicate that single-pill antihypertensive combinations (SPC) have greater rates of adherence and more effective lowering of blood pressure than free-drug combinations (FC). SPC therapy has been used in Korea for the purpose of achieving optimal blood pressure control. However it is questioned whether such existing positive evidence toward SPC from western countries can be found in the Korean population. METHODS: This study compared compliance, persistence and blood pressure change of SPC versus FC using the medical charts of 1,940 patients from 17 Korean general hospitals (GH1-17). The hypertensive patients with SPC or FC prescription, more than 40 years old, no history of hospitalization, visited GH1-17 from January 1, 2010 to December 31, 2011 were included. Compliance was compared using the Medication Progression Ratio (MPR), calculated as the ratio between the days medication was taken and days in a time interval. Persistence was measured as the number of days from the index date to the therapy discontinuation date. The blood pressure (BP) change was calculated as the difference between the first and the last visit. RESULTS: Overall compliance measured by MPR was 0.71 for the SPC group and 0.69 for the FC group, with the difference being statistically significant. This was especially evident for SPC patients in the 40~64 year age group (0.71 for SPC, 0.69 for FC) and patients with two or more comorbidities (0.73 for SPC, 0.69 for FC) (P= 0.0011). However, no statistical significance was observed for the difference both in persistence and the BP change between the two groups. CONCLUSIONS: Our study suggests that compliance tends to be improved by the use of SPC compared with FC. Unlike the previous western studies, it was hard to find a significant increase in persistence or BP change with SPC therapy in this study.