The aim of the presented paper is to describe the mechanisms of autobiographical memory, especially processes such as memorizing, memory retrieval and reinterpreting memories, which may be useful in work of family therapists during genogram sessions. The changeability of the content of memories, especially when an original event is transformed during its memorization and retrieval, are presented. It is also shown how these processes can facilitate healthy reinterpretation of the elements of the memories. Autobiographical memory is an unstable and flexible phenomenon and the records of past events change over time. If family therapists take it into consideration, they create a new space for the therapists-families interactions. Patients may believe that what they reminiscent are the real events and give them an obvious interpretation, although the psychological knowledge indicates that this interpretation is already adapted to the auditorium of listeners. A genogram session presents a unique opportunity to modify the way patients interpret important events from the past. A new, more “friendly” way of how each partner understands his or her past fosters more mature explanation of present and past behaviour. Family therapists may benefit from taking into consideration memories as a fluid matter, which is not a reliable record of past events but rather a result of reflection of the relational and cognitive processes that occurred in the past, and is still in progress during a genogram session. This could be supported by therapists when they create a good alliance with the family, invite everyone to share memories about families of origin, or stimulate the dialogue about these memories.