The 1983 register of medical and dental practitioners was used to describe the provincial and urban-rural distribution of non-specialist medical practitioners. The number of medical practitioners who will be registered in 1990 was estimated on the basis of current accrual and loss patterns. The number required by 1990 was estimated on the basis of the projected population growth using a linear prediction model in which the proportion of blacks resident in urban regions was varied. The requirements were based on doctor/population ratios either remaining as they were in 1980 or improving by 1990. We found that for South Africa there were 2 198 people per doctor. However, there were more people per doctor in rural regions than in urban regions, with the rural Cape Province the only rural region with fewer than 6 000 people per doctor. In black national states there were more than 14 000 people per doctor. There appears, therefore, to be a need for redistribution of medical practitioners to the rural regions. We estimated that, should doctor/population ratios in 1990 remain as they were in 1980 with only a modest increase in black urbanization, there would be enough medical practitioners registered in 1990 at current accrual rates. Should rural ratios be improved to 1:5 000 and urban ratios to 1:1 000 as proposed in the National Health Services Facility Plan, there will be fewer doctors registered than are needed in 1990, particularly if black urbanization increases markedly.(ABSTRACT TRUNCATED AT 250 WORDS)