Swine have been implicated as the intermediary host for transmission of avian influenza to humans, and there have been several cases where swine viruses have been transmitted to humans (Myers et al., 2007). Thus continuous surveillance becomes important in the context of predicting epidemics and pandemics. This study describes the phylogenetic analysis of four swine viruses isolated from humans in Kazakhstan, and is probably the first phylogenetic study of swine influenza viruses from Central Asia (excluding Mongolia) in the known literature. The viruses were found to be highly identical in their entirety to the classical swine isolate A/sw/Jamesburg/1942 (except for the HA of A/Almaty/32/98 which was identical to WS/1933), consistently being placed at the root of the classical swine lineage. On amino acid analysis, the viruses displayed mutations on HA and ribonucleoproteins which putatively disrupt antigenic recognition of the virus. The presence of viruses relatively unchanged 6 decades after their initial isolation are explained by a combination of laboratory leaks in southern USSR in 1980s, low population density of Kazakhstan, and finally the low evolutionary rate of classical H1N1 swine viruses in pigs.