The thesis describes the phenomenon women’s health and illness experiences following a myocardial infarction (MI). The purpose of the thesis is to explore women’s experiences of their care and health processes, as well as their experiences of body, lifeworld and meaningful relationships related to the illness. A reflective lifeworld approach, based on phenomenological philosophy, is used. The thesis is comprised of four studies; three are based on interviews with a total of 26 women following an MI, followed by a fourth, theoretical, study. The first study explores women’s experiences of care and health processes following an MI, with a particular focus on well-being and participation (I). The findings show that an MI is an event that suddenly interrupts the ordinary life of the women. Participation is a sense of being involved in their own health and care processes, which may also encourage them to take responsibility for health promoting activities in a healthy and meaningful way. The second study explores women’s lifeworld experience of their bodies and lives following an MI (II). This study finds that an MI, as a major event in the women’s lives, influences and restricts their everyday activities over a long period of time. Following the illness, they live with an existential uncertainty about their life and the heart, and this feeling entails suffering for them. The third study explores the meaning of close relationships and sexuality to women’s health and well-being following an MI (III). The mmeaning of close relationships appears to be vitally intertwined with their long-term health process; both health processes and relationships are affected after an MI. The suffering following an MI can be compared to taking a fall, where meaningful close relationships can function as a safety net that catches the women in their fall. The fourth study is a concept development aimed at elucidating the meaning of the concepts uncertainty, control, secure and risk in relation to the thesis phenomenon and the findings of the empirical interview studies (IV). The existential uncertainty is an important matter in the women’s health processes. In these processes the concepts control, secure and risk play a central role. Women who have suffered an MI want to be as safe as possible in order to live well. The analysis illuminates a paradox, that the women’s ambition to achieve greater safety may lead them into an even greater experience of uncertainty. The conclusion is that women’s experiences of health and illness can be described as a journey characterized by existential uncertainty. The women’s lives go through different existential phases following an MI, which is a major event. They are not prepared for the reactions that this event causes and are in need of support and guidance to manage their illness experiences. If acknowledged and well met, the significance and meaning of the women’s reactions and experiences can give impetus and energy to their health processes