BACKGROUND: Sperm concentration needed for artificial insemination (AI) to obtain reasonable fertility, taking into consideration genetic value of bull and numerous others components is one of the essential constituents for successful breeding program. AI-doses containing low sperm numbers are increasingly widespread to optimize the benefit of elite bulls, as well as to accommodate an eventual wider application of sex-sorted semen. Viability is reduced when higher dilutions of semen are carried out for production of low sperm doses. The reduction in viability may be due to dilution effect as well as due to dilution of numerous essential constituents in seminal plasma at higher dilutions. Fertility level of bull may play a pivotal role in determining the cryosurvival of low sperm doses and viability of low sperm doses may vary among bulls. This paper attempts to highlight studies dealing with the effect of dilution on cryosurvival of low sperm doses.