Low-risk prostate cancer, defined as Gleason Score 6 or less with PSA <10 ng/ml, is diagnosed in about half of men undergoing screening. Approximately 30% of men diagnosed with low-risk disease harbour high-grade cancer that is unrepresented on the biopsy. Moreover, a small percentage of low-grade cancers have molecular alterations that result in progression to aggressive disease. Favourable-risk prostate cancer should be managed with close follow up. Active surveillance is appropriate for most patients with low-risk disease, and radical treatment should be reserved for cases in which higher-risk disease is identified. In turn, focal therapy aims to preserve tissue and function in men who have been diagnosed with localized disease, and should be offered to men with higher risk disease at baseline, as an alternative to whole-gland radiation or surgery, or when the patient transitions from low-risk to higher-risk disease. The two strategies should be viewed as complementary elements of care that can be applied in a risk-stratified manner. In this Review, we discuss the rationale and current status of active surveillance-which constitutes a standard of care in most evidence-based guidelines-and comment on whether and when focal therapy should complement it in those men wishing to continue a tissue-preserving strategy.