Benign prostatic hyperplasia (BPH) can impact significantly on a patient’s quality of life (QOL), including sexual functioning. With increased life expectancy, this aspect of the disease is becoming increasingly important. Symptom severity can be measured using a number of instruments, the most common one being the International Prostate Symptom Score (IPSS). A number of studies have shown that symptom severity is correlated with decreased QOL, i.e. the more severe the symptoms, the greater the impact on QOL. Specific questionnaires have been developed to address the issue of sexual function, including the Brief Sexual Function Inventory and the International Index of Erectile Function. Importantly, these instruments can usefully be applied to assess the effect of the various therapies for BPH on sexual function. In general, the α1-blockers have minimal impact on sexual function, compared with finasteride, which can affect libido, ejaculation and erectile function itself.