We evaluated the effects of vardenafil on testicular androgen-binding protein secretion (ABP). Bilaterally obstructed azoospermic (OA)-men (n = 19) (group A) underwent unilateral testicular biopsy. A group of nonobstructed azoospermic (NOA)-men (n = 68) (group B) underwent bilateral testicular biopsy. ABP secretion in vitro by testicular tissue was assessed in each participant of every group. In addition, intracytoplasmic sperm injection (ICSI) cycles were performed in several couples of group A or group B using frozen/thawed spermatozoa from the biopsy material. Ten OA-men (group A1), 14 NOA-men (group B1), and nine different NOA-men (group B2) had been positive for spermatozoa in the biopsy but pregnancies were not achieved in the respective female partners. Men of groups A1, B1 and B2 were treated with vardenafil, vardenafil and L-carnitine respectively. Then, the men of groups A1, B1 and B2 underwent a second testicular (unilateral) biopsy. Within the group A1 and within the group B1, ABP secretion rate was significantly larger after vardenafil treatment than prior to vardenafil treatment. In addition, fertilisation rates in ICSI cycles within groups A1 or B1 were not affected by vardenafil administration. Vardenafil administration in NOA-men increased ABP secretion and did not affect detrimentally the presence of testicular foci of advanced spermatogenesis.