The progression of benign prostatic hyperplasia (BPH) can be defined as a deterioration of clinical variables such as lower urinary tract symptoms (LUTS), health‐related quality of life and peak flow rate, increased prostate size, or unfavourable outcomes such as acute urinary retention (AUR) and BPH‐related surgery. The natural history of BPH is best analysed from longitudinal studies of community‐dwelling men. In the Olmsted county study, which followed for 12 years a randomly selected cohort of 2115 men aged 40–79 years, there was an average increase in the International Prostate Symptom Score (IPSS) of 0.18 points per year, ranging from 0.05 for men in their fifties to 0.44 for those in their seventies. There was also a decrease in peak flow rate of 2% per year and a median prostate growth of 1.9% per year. The cumulative incidence of AUR was low (2.7% over 4 years). Information can also be collected from the placebo arms of controlled studies of men with symptomatic BPH, although the strict trial inclusion criteria and indeed the taking of a placebo itself introduce biases which limit the analysis of the natural history of the disease in this way, and its applicability to the general population. Hence, in the Medical Therapy of Prostatic Symptoms study, there is clear evidence that symptom deterioration, defined by a worsening of the IPSS of ≥ 4 points, was by far the most prevalent progression event (79.5%), with a cumulative incidence of 14% over a mean follow‐up of 4.5 years. As in the longitudinal community‐based studies, AUR was rather uncommon (14.8% of overall progression events) with a cumulative incidence of 2%. BPH‐related surgery, which was a secondary criterion in the study, was required in 5% of men. Similar conclusions can be drawn from a 2‐year placebo‐controlled study (ALTESS) assessing the impact of alfuzosin 10 mg once daily on LUTS/BPH progression in 1522 men with symptomatic BPH at high risk of developing AUR. Symptom deterioration was clearly the main progression event, with a cumulative incidence of 16.8%, compared to BPH‐related surgery (6.5%) and AUR (2.2%). Thus, there is evidence from longitudinal studies, and to a lesser extent from the placebo arms of large controlled studies, that BPH is a progressive disease. Symptom worsening is by far the most frequently occurring progression event. Identifying those patients at risk of BPH progression is crucial to optimize their management.