Traumatic stress is a type of environmental experience that can modify behavior, cognition and physiological functions such as metabolism, in mammals. Many of the effects of traumatic stress can be transmitted to subsequent generations even when individuals from these generations are not exposed to any traumatic stressor. This book chapter discusses the concept of epigenetic/non-genomic inheritance of such traits involving the germline in mammals. It includes a comprehensive review of animal and human studies on inter- and transgenerational inheritance of the effects of traumatic stress, some of the epigenetic changes in the germline currently known to be associated with traumatic stress, and possible mechanisms for their induction and maintenance during development and adulthood. We also describe some experimental interventions that attempted to prevent the transmission of these effects, and consider the evolutionary importance of transgenerational inheritance and future outlook of the field.