Abstract Benign prostatic hyperplasia (BPH) is a condition characterized by an increase in both the stromal and glandular elements of the prostate gland, leading to an overall increase in its size. BPH arises as nodular growth in the periurethral glands of the transitional zone of the prostate. Histological evidence can be found as early as the fourth decade of life. BPH is the most common benign tumour in men and the risk of its development increases with age: evidence of BPH is found in the prostates of 70% of men aged 70 and the prevalence approaches 100% by 80 years of age. BPH is more prevalent in ‘Western’ societies than in the Far East, and in the USA it is more common in the black population than the white. The terminology surrounding benign prostatic disease has been confused, but now there is consensus that: • the term BPH denotes the histological entity • the term benign prostatic enlargement (BPE) denotes a clinical finding on rectal examination • the term benign prostatic obstruction (BPO) denotes a urodynamically-defined state.