Inclusion Criteria:

• Males 18 to 64 years
• Males with ED for more than six months, according to the NIH Consensus Statement (inability to attain and/or maintain penile erection sufficient for satisfactory sexual performance)
• Stable heterosexual relationship for more than 6 months
• The subject must make at least four attempts at sexual intercourse
• Documented, dated, written Informed Consent

Inclusion Criteria: Partner

• Females 18 years, and older
• Stable, heterosexual relationship for more than 6 months with male ED subject
• Documented, dated, written Informed Consent
• Motivated to support treatment for male partner's ED
• Absence of significant sexual dysfunction as assessed by the total score on the FSFI16 > 23.55

Exclusion Criteria:

• Any unstable medical condition or substance abuse disorder that, in the opinion of the Investigator, is likely to affect the patient's ability to complete the study or precludes the patient's participation in the study
• Subjects who are taking nitrates or nitric oxide donors
• Subjects who are taking the following inhibitors of cytochrome P 450 CYP 3A4: very potent HIV protease inhibitors (ritonavir, indinavir), the anti-mycotic agents traconazole and ketoconazole (topical forms are allowed) or erythromycin
• Known hypersensitivity to vardenafil
• Presence of significant penile anatomical abnormalities (e.g. penile fibrosis or Peyronie's disease)
• History of retinitis pigmentosa
• Unstable angina pectoris
• Severe chronic or acute liver disease
• Premature ejaculator (defined as IELT < 2 minutes)
• Subjects who were taking alpha blockers
• Lost of vision of one eye because of NAION

Exclusion criteria: Partner

• Presence of sexual dysfunction as assessed by the FSFI16 < 23.55
• Any unstable medical condition or substance abuse disorder that, in the opinion of the Investigator, is likely to affect the partner's ability to complete the study or precludes the partner's participation in the study