INTRODUCTION: To evaluate erectile function among men who had undergone laparoscopic radical prostatectomy and received postoperative medical therapy for erectile dysfunction. MATERIALS AND METHODS: We performed a prospective study in men who underwent laparoscopic radical prostatectomy between September 2003 and November 2005 at our center and who received penile rehabilitation after surgery. All patients had antegrade interfascial dissection. They received 10 mg tadalafil on the fifth postoperative day and continued to receive it every other day, regardless of erectile function. Intracavernous injection of alprostadil was initiated at 3 or 6 months depending on response to treatment with tadalafil. Follow up evaluations were done at 3, 6, 12, 18 and 24 months. Oncologic and functional outcomes and compliance were assessed. Patients filled in International Index of Erectile Function-5 (IIEF-5) questionnaires. RESULTS: Of 1078 men who underwent laparoscopic radical prostatectomy during this time, 586 patients met inclusion criteria, complied with the study medication, and had complete data for 24 months. The patients had a median preoperative baseline IIEF-5 score of 22. A total of 150 patients (26%) underwent unilateral nerve-sparing surgery, while 436 patients (74%) had bilateral nerve-sparing surgery. At 24 months, 35% of patients who underwent unilateral nerve-sparing surgery and 68% of patients who underwent bilateral nerve-sparing surgery reported having sufficient erectile function for intercourse without using intracavernous injection of alprostadil. At 24 months after surgery, the median IIEF-5 score was 13 (1-25) for the whole cohort, 5 (1-25) for patients who had undergone unilateral nerve-sparing surgery, and 15 (1-25) for patients who had undergone bilateral nerve-sparing surgery. CONCLUSIONS: The findings suggest that adequate patient selection and postoperative medical intervention allows the preservation or recovery of erectile function after laparoscopic radical prostatectomy. Inaccurate selection of patients and postoperative assessment might explain inferior erectile function results following this surgery.