OBJECTIVES: A pilot care managing programme was introduced in Hungary in 1999. The conceptual foundations of the Hungarian implementation of managed care is closer to what was called the GP fundholding in the UK than HMOs in the USA. The purpose of the study is to analyse the changes in the number of enrolees in the care managing programme. METHODS: The data derive from the financial database of the Hungarian National Health Insurance Fund Administration (NHIFA) covering the period 1999-2007. We identified the average annual number of persons enrolled to Care Managing Organizations. The Hungarian CMOs was financed through a risk adjusted capitation fee and the health services covered by CMOs were defined in legal regulations. RESULTS: The total number of the Hungarian population was around 10 million people (100 %) during the study period. Since the beginning of the programme (1999) the total number of persons covered by the care managing programme increased from 158,984 (1.5 % of the Hungarian population) to 601,915 persons (5.9 %) in 2003 and to 1,961,025 (19.4 %) in 2005. After this peak, the number of enrolees decreased to 1,823,732 persons in 2006 and 1,409,475 persons in 2007. Later the Hungarian managed care pilot programme was cancelled. CONCLUSIONS: With the development of the Hungarian care managing system, the average number of enrolees increased. This increase resulted in larger risk-pooling structure providing a more stable environment for Care Managing Organizations.