In this paper a dynamic model is presented which describes the development of the demand for specialistic medical care in The Netherlands, during the period 1960-1972. The "regionally correlated, time-wise auto-regressive" model is consistently estimated from a time-series of cross-sections, using a modified Aitken estimator. The dependent variables are the number of publicly insured patients referred from general care to specialistic care, and the amount of care consumed per patient referred. As independent variables we took demographic factors, the supply of different levels of medical care and the insurance system. The estimation results show a.o. important substitution possibilities between general and specialistic care, and a significant influence of supply and supply-related variables on the demand for specialistic care.