This study used in-depth interviews to explore the experiences of parents who were re-contacted with new genetic results many years after the death of a child with a mitochondrial disorder. At the time of their child's illness, parents had consented to a tissue sample being taken to help with diagnosis of a suspected mitochondrial disorder, and subsequently further DNA testing identified the genetic cause. Parents did not express negative feelings about being re-contacted with new information, and hoped that continuing research might help other families. Positive aspects included relief from feelings of guilt over the cause of the child's disorder, and having accurate genetic information available for surviving children. Difficult emotional and psychosocial implications included contradictions to previous beliefs about inheritance, deciding how and when to communicate information to surviving children, and coping with new fears for the mother's health if a gene located in the mitochondrial DNA was identified. In half of the families the new results significantly altered the parents' understanding of the inheritance pattern. This study highlights the impact of new genetic information offered after a delay of several years, which has the potential to re-open feelings of grief and uncertainty and can present a new inheritance scenario for which research participants or their families are unprepared. Health professionals involved in conveying genetic research results can help to support families through this process.