Inclusion Criteria:

- scheduled to undergo Bilateral nerve-sparing radical prostatectomy (BNSRP) for
organ-confined, non-metastatic prostate cancer

- have a normal preoperative erectile function score of more or equal to 22 at
screening(as evaluated by International Index of Erectile Function - Erectile
Function domain (IIEF-EF))

- develop Erectile Dysfunction (ED) (defined as the consistent inability to achieve
and/or maintain an erection sufficient to permit satisfactory sexual intercourse)
after surgery

- have an interest in resuming sexual activity as soon as possible after surgery and
anticipate having the same adult female sexual partner during the study

- agree not to use any other treatment for ED, including herbal and over-the-counter
(OTC) medications, during the study

- does not require the initiation of adjuvant therapy for prostate cancer

Exclusion Criteria:

- history of ED

- have received previous or current treatment with tadalafil or any other PDE5
(Phosphodiesterase Type 5) inhibitor

- have undergone, or plan to undergo, radiation or hormonal therapy for prostate cancer

- have a history of prostatic surgery or prostatic physical treatments

- have a history of diabetes mellitus

- have a history of galactose intolerance, lapp lactase deficiency, or
glucose-galactose malabsorption

- have clinically significant renal insufficiency as determined by the investigator