Ensuring an adequate and sustainable number of health workers, with appropriate knowledge and skills, is a key health policy issue worldwide. The aim of this thesis was to develop a model for simulating the dynamics of referral to specialist training of medical doctors in the Republic of Croatia and systematically examine different scenarios to assess the optimal strategy to ensure a stable supply of specialists in various specialties and correct the gap between supply and demand. Stella Architect v1.9.1 software package with a graphical interface for creating and simulating models using the system dynamics method was used to create a simulation model and to perform simulation experiments. Changes in the number of physicians and their age distribution are projected in the context of expected future changes in the Croatian population under different scenarios covering the period from 2020 to 2035. A multi-part model of system dynamics has been developed, covering all phases of education and work of specialist physicians, from enrolment in medical studies through specialist training and working life in the health system (or another system that employs physicians) to retirement. The results of simulation modelling of different scenarios indicate that the current total enrolment quota for the study of medicine in the Republic of Croatia of 590 students per year is sufficient to meet the needs for medical doctors in the future until 2035.