To conduct an intersectional analysis of relations between gender and age in the health behaviors of middle-aged men, informed by cross-national comparison between Finland and the United States. Thematic and discourse analysis of data from interviews conducted among professional and working-class, middle-aged men in the U.S. and Finland. Respondents report that middle age inspires them to regard many bodily changes as more than transitory; and they assume a sense of responsibility that can lead to greater self-care. Men reported using such strategies as discipline, routine, and monitoring in their attempts to forestall aging. The men face contradictions: While they may adopt ideologies of masculinity and control and accept responsibility for influencing their health, their bodies may also present them with age-based limitations to their abilities to do so. How men respond to these changes varies by context, including their aging and these nations' different systems of health care.