Blood from 304 newborn infants of Melbourne, Australia, was examined for 9 polymorphic systems (red cell antigens ABO, MNSs, Rh, Kell, Duffy and Kidd, the red cell enzyme ESD and serum proteins GC and TF) in order to investigate the evolution of the Melbourne gene pool since 1975. Immigration patterns have changed considerably over the past 10 years, especially with an increase in refugees from South-East Asia. Three ethnic categories were identified on the basis of surnames; British Isles, Europe and Middle East, and South-East Asia, with the respective allele/haplotype frequencies of these groups being similar to those found in the source regions. Analysis by an R-matrix indicated that the Asians form a very distinctive subpopulation, but that their influence is minimal to date.