The doctor will obtain a thorough medical history to find out about past pelvic surgery, diabetes, cardiovascular disease, kidney disease, and any medications the man may be taking.

The physical examination may include a genital examination, a measurement of blood flow through the penis, hormone tests, and a glucose test for diabetes.

In some cases, nocturnal penile tumescence testing is performed to find out whether the man has erections while asleep. Healthy men usually have about four or five erections throughout the night.

The man applies a device, called a Rigiscan, to the penis before going to bed at night, and the device measures whether he has had erections. If a man is able to have normal erections in his sleep, this finding suggests a psychological cause for his impotence.