The epigenome undergoes a reprogramming process during gametogenesis and early embryogenesis. Therefore, it is believed that epigenetic information cannot be transmitted across generations. However, the occurrence of epigenetic transgenerational phenotype suggests that certain epigenetic marks may escape reprogramming. Although the existence of such a mode of inheritance has been controversial, there is increasing evidence that epigenetic memory does occur in mammals. Due to the reversibility of epigenetic modification, the epigenome is easily changed by a variety of environ-mental factors, such as chemicals, nutrition and behaviour. Therefore, it provides a potential mechanism for the transgenerational transmission of the impact of environmental factors. The purpose of this review is to introduce the concept of epi-genetic transgenerational phenotype, to discuss the epigenetic reprogramming and the molecular mechanism of epigenetic transgenerational transmission, and to list some environmental factors that are associated with epigenetic transgenerational diseases.