Development of a model for simulation of the needed number of specialists of different specialties in the Republic of Croatia by the year 2035 based on the expected changes in size and age structure of population and experts' estimates of the needs. The model will be implemented in the form of a computer program based on the estimated most potent predictors. The developed model will be used as a tool for the simulation of different scenarios for specialist education combined with other factors like migration flows, changes in retirement age and skill mixing in order to compare different possibilities and options for the renewal of the Croatian healthcare personnel. Results will enable the development of recommendations for decision making and the adoption of a rational plan of referral to specialist training. Indirectly, developed model will be useful for needs assessment and simulation and planning of workforce renewal of other health professionals and for other countries.