Allogeneic haematopoietic stem cell transplantation (hereafter HSCT) is an established treatment which offers a potential cure for a variety of diseases, mainly haematological malignancies. However, the treatment is also associated with significant risks of acute complications and late side effects, including mortality. The donor is either a relative, most often a sibling, or an unrelated registry donor. Methods for donating stem cells are bone marrow harvesting or peripheral blood stem cell collection. The most common and transient side effects from stem cell donation are fatigue, headache, bone and muscle pain. Major side effects are rare but there is a small risk of fatalities and serious adverse events. To facilitate the provision of adequate information and care of patients undergoing HSCT and their sibling donors there is a need to explore and study their situations and experiences. This thesis aims to investigate patients’ and sibling donors’ perspectives of HSCT.The first study investigated changes in the patients’ quality of life (QoL) from before HSCT to 100 days and 12 months after the transplantation, and identified factors associated with the changes. The study was completed by 40 patients who answered the questionnaires (FACT-BMT and FACIT-Sp) on all three occasions. The majority of the dimensions covered in QoL deteriorated from before and up to 100 days and 12 months after HSCT, except for the emotional well-being which improved. The factors associated with reduced QoL over time were significant infections, female gender and transplantation with stem cells from a sibling donor. Factors associated with improved emotional well-being over time were absence of significant infections and marital status ‘other than married/cohabiting’.In the second study an information and care model (IC model) for potential sibling stem cell donors was evaluated. A questionnaire survey was answered by 148 siblings who had been informed about and asked to undergo HLA typing by the IC model. The majority of the potential sibling donors were satisfied with the information and care they had received. However, areas for improvement were highlighted, such as a wish to have the results from the HLA typing conveyed through personal contact and that the complicating influence of health professionals and relatives on their decision to undergo HLA typing and possible donation could be prevented.In the third study ten HSCT patients were interviewed immediately before transplantation regarding their experiences of having a sibling as donor. The results, with the main theme Being in no man’s land, show that the patients are in a complex situation before transplantation, experiencing a mixture of emotions and thoughts. In the fourth study ten sibling donors, where the recipients were the participants in Study III, were interviewed regarding their experiences before donation of being a stem cell donor for a sick sibling. The main theme, Being a cog in a big wheel, in the results shows that the sibling donors go through a complex process before donation, a situation they have not volunteered for but have got into accidently, experiencing a mixture of emotions and thoughts. The results also show that the sibling donors do not usually reveal their thoughts and emotions about being a donor to anyone. The patients’ and sibling donors’ experiences can be seen to be connected to each other, however, they have not usually talked to each other about their emotions and thoughts. To conclude, HSCT patients’ overall QoL and the majority of the dimensions of QoL deteriorated from before until 100 days and 12 months after HSCT, while their emotional well-being improved. The privacy and free choice of potential sibling donors have to be respected and the information and care of patients and their sibling donors should be kept separate. Health professionals should bear in mind that both patients with a sibling as donor and sibling donors are in complex situations before transplantation and donation, experiencing a mixture of emotions and thoughts. Further, it is important to individualize the information and care for HSCT patients and their sibling donors in a supportive and professional manner.