Demonstrations that ageing and life-span can be manipulated in model animal species have increased hopes that the length of the human life-span may also be dramatically extended. The possibility of human life-span extension has provoked debate amongst bioethicists. Proponents of life-extension cite the benefits of a longer and healthier life. Opponents argue that these technologies: violate human nature; may not necessarily increase the quality of life; and, they will lead to overpopulation and social strife that outweighs any benefits to individuals. Others see problems of equity and justice in access to any potential life-extension technologies. The attitudes of members of the public have largely been neglected in ethical and policy discussions of human life-extension. In the absence of empirical evidence on public attitudes, proponents and opponents have assumed either widespread public enthusiasm for life-extension or strong opposition because of concerns about its moral acceptability or its adverse social consequences. All agree that public attitudes could be a powerful facilitator or a major obstacle to the development of life-extending technologies. The goal of this thesis is to characterise public attitudes towards life-extension and describe factors that influence these views. It examines the following questions: (1) What is the prevalence of public support for (or opposition to) life-extension research? (2) How much interest is there among the public in using a technology that could increase life-span by slowing ageing? (3) What issues are important to members of the public in forming their attitudes? (4) What ethical issues, if any, do members of the public identify? (5) Are these ethical and moral issues the same ones expressed by ethicists and social scientists? (6) How do these ethical attitudes affect their overall interest in, or support for, life-extension? (7) How are attitudes towards life-extension related to demographic characteristics such as age, gender, education, and religious beliefs? Three empirical studies were designed using a mixed methodology to answer these questions. Study 1 (focus groups) and Study 2 (individual interviews) were qualitative investigations of public attitudes towards life-extension. The results of these two studies informed the design of Study 3 - a quantitative survey of attitudes towards life-extension via telephone interviews with 605 adult members of the Australian public. Participants in Study 3 were presented with a vignette outlining the prospect of a life-extension pharmaceutical that could increase life-span to 150 years by slowing the ageing process. They were then asked to express their level of agreement with a series of statements about ethical, social and personal implications of life-extension, and their overall support and interest in using such a technology. All three studies found mixed public attitudes towards the development and use of life-extension technologies. Participants in Studies 1 and 2 were concerned about whether life-extension would be accompanied by good quality of life. Studies 1 and 2 also suggested that participants were concerned about social and ethical issues that included: the potential impact on society; whether life-extension was “natural”; and whether access to life-extension technologies would be fair and equitable. Study 3 confirmed the diversity of public views identified in the qualitative phase. While 65% supported such research, only 35% said that they would use a life-extension technology if one became available. Men were more supportive of research and more disposed to use life-extension technologies than women. 58% of participants expressed ethical or moral concerns about life-extension technologies. When asked to weigh up the potential benefits and negatives that they identified as important, almost half (48%) said that life-extension technologies would do more harm than good to society, and 40% thought that taking a life-extension pharmaceutical would do them more harm than good personally. Study 3 also showed that valid scales could be constructed to assess the strength of concerns about social and ethical issues. These scales were: personal benefits/negatives; social benefits/negatives; and natural concerns. Higher levels of support for using and developing life-extension technologies were associated with higher levels of perceived personal and societal benefits from life-extension. Participants who had more ethical concerns, and perceived more personal and social negatives were less likely to support or express an interest in using life-extension technologies. Perceptions of personal and social benefits, and having concerns about the “naturalness” of life-extension were the best predictors of support or interest in using life-extension technologies. This thesis shows that public attitudes towards life-extension are more varied than some ethicists have assumed. While there are substantial minorities who were clearly “pro” or “con”, many members of the public are concerned about ethical and social issues. It would be unwise for researchers of life-extension not to take account of public attitudes and concerns if they hope to foster public support for their work.