Active surveillance is a new strategy that aims to individualise therapy by selecting only those men with significant cancers for curative therapy based on early evidence of disease progression. Active surveillance must be distinguished from watchful waiting, which for decades has described a policy of observation with the use of palliative treatment for symptomatic progression. The rationale for active surveillance is discussed, based on our knowledge of the natural history of PSA-detected early prostate cancer. The initial results of active surveillance have demonstrated its feasibility. Ongoing studies seek to optimise the active surveillance protocol, and to determine the long-term outcomes. Looking ahead, dietary intervention in men on active surveillance could become an important new paradigm for prostate cancer management.