Egg freezing was initially used as an intervention for iatrogenic ovarian insufficiency. Nowadays, it is not considered an experimental procedure, and it is increasingly popular among healthy women who wish to maintain their reproductive potential (fertility preservation). This review summarises the evidence on egg freezing technology, reproductive outcomes and long-term effects, as well as its psychological and socioeconomic implications. Egg freezing technology is advancing, with vitrification being the current method of choice, due to its effectiveness. The reproductive outcomes following egg freezing appear to be promising, though the strong negative association with maternal age has to be taken into consideration. Unfortunately, data on long-term outcomes are missing, raising safety issues. Egg freezing has several socioeconomic implications involving health risks, as well as financial and psychological factors.