OBJECTIVES: On the February 15, 2007 new forms of co-payment were introduced in Hungary: visit fee (300 HUF/visit) in the outpatient care and hospital daily fee (300 HUF/day) in the inpatient care. The aim of this study is to analyze the effect of the introduction of hospital daily fee on the number of inpatient admissions to acute care hospital wards in Hungary METHODS: The data derive from the financial database of the National Health Insurance Fund Administration (OEP) of Hungary covering the period of 2006-2008. We analyzed the number of admissions during a 10 months period before (from March 2006 to January 2007) and after (from March 2007 to January 2008) the introduction of daily fee. Data from February 2007 were omitted. RESULTS: During the 10 months period before the introduction of hospital daily fee the total number of admissions was 2,285,011, while during the 10 months period after the introduction of daily fee it decreased to 1.940.880. The average monthly number of admissions was 207,728 before and 176,444 after the introduction of daily fee. This represents a 15.1% decrease in the number of acute care admissions. CONCLUSIONS: The introduction of hospital daily fee in the Hungarian inpatient care resulted in a significant decrease of acute inpatient care admissions. However we do not have information whether admissions failed to be realized were really unnecessary or not. Other elements of the health care reforms could have also influenced the number of admissions.