This study describes the daily life and management strategies of young informal carers of family members or friends with mental illness. Twelve young adults (three men and nine women; 16-25 years old) in Sweden were voluntarily recruited between February and May 2008. Data collected through eight individual semi-structured interviews and one focus group interview were analysed using qualitative content analysis. The findings revealed nine subthemes that were further grouped into three main themes: showing concern, providing support and using management strategies. Participants lived in constant readiness for something unexpected to happen to the person they cared for, and their role in the relationship could change quickly from family member or friend to guardian or supervisor. Supporting a friend was considered as large a personal responsibility as supporting a family member. Their management strategies were based on individual capacities and their ability to step aside should the situation become too demanding. These young informal carers need support in caring for the mentally ill. As the internet becomes increasingly fundamental to daily life, support could be provided most effectively through person-centred web sites.