Breeding Russian hamsters is simple as they are sociable and will live together in mixed sex pairs or groups and breed naturally. Pairs or groups of Russian hamsters are best established at a young age as introducing older hamsters can often result in fighting.
Males will naturally mate with the females when kept together and when in season the female will allow the male to mount her. He will thrust a few times before dismounting and washing himself and then often will remount and mate again. The male will usually mate with the female several times. Not all unproven males will get a female pregnant after the first mating and some males may need to mate several times before a successful pregnancy occurs. The actual mating may not always be observed.
A female Russian hamster comes into season soon after giving birth, so a male will often mate with the female again once she has given birth.