The analysis of dynamics of population of saiga in Kazakhstan testifies that in the first half of the last century under the influence of anthropogenous and ecological factors their number was at the critical level: no more than 3.0 thousand heads. After taking measures to a hunting ban in 1958-1998 this hoofed animal was one of the most numerous hunting-trade types with a population of 1.0 million heads. However, since 2000 years their livestock decreased at 3-10 times owing to unlimited hunting (poaching) and an epizooty of pasteurellosis, which caused a massive die-off. According to authors the death of saigas from this infection is caused by decrease in the genetic variety which was caused by effect of "a bottle neck". Sharp falling of number of animals led to impoverishment of a gene pool and loss of immunity to this illness. It threatens to decrease in number of saigas soon to an absolute minimum. For the purpose of preservation of a saiga authors offer a number of urgent measures. Among them implementation of unprecedented aviation vaccination of animals spraying of water solution of an anti-pasteurellosis vaccine of grassy vegetation from helicopters; carrying out genetic researches by DNA analysis methods for studying of genetic distinctions of population and search of the key genes controlling resistance of a species to an infection; realization of strategy of restoration of a genetic variety of a saiga interspecific crossing of nominal and Mongolian subspecies. Only acceptance of the specified measures will allow keeping steadily a saiga as a species in fauna of mammals of Kazakhstan.