While some argue that gender differences, which refer to the social classification into ‘masculine’ and ‘feminine’, have their source in ‘culture’, others argue there is no need to have an absolute dichotomy between culture and nature, or between constructionist and anti‐constructionist epistemologies. Although there has been much theorising about the body, until recently little attention has been paid to empirical evidence. This paper looks at the way in which prostate cancer and its treatment affects men's bodies, their roles and sense of masculinity. Interviews were conducted with 52 men, exploring their experiences of prostate cancer. Findings suggest that many men are reluctant to consult their doctors, because ‘men don’t cry’, thus reinforcing the notion that ‘masculinity’ is a social construction. However, while the illness and the side effects of surgical and radiotherapy treatments sometimes led to impotence and incontinence, the treatments that involved hormones were reported to have an additional, sometimes profound effect on libido, energy, ability to work, body shape and competitiveness. These side effects reduced some men's sense of masculinity. We conclude that the physical body as well as culture should be considered when trying to explain what it means to be masculine, and how illness may affect men's sense of masculinity.