Study is a clinical study assessing the effect of oral tadalafil 10mg or 20 mg on psychosocial aspects and quality of life of erectile dysfunction patients and to compare tadalafil with previous oral erectile dysfunction medication. Study period is 13 weeks. Study patients fill in quality of life questionnaires and treatment satisfaction questionnaires.

Inclusion Criteria:

• have a history of erectile dysfunction (defined as a consistent change in the quality of erection that adversely affects the patient's satisfaction with sexual intercourse)of at least 3 months duration
• have been using any oral prescription medication,but not tadalafil, for erectile dysfunction for a minimum period of 3 months before visit 1
• have responded to previous erectile dysfunction medication as assessed by the investigator

Exclusion Criteria:

• exhibit evidence of clinically significant hepatobiliary disease (including jaundice) at visit 1
• cardiovascular exclusion criteria: history of chronic stable angina treated with nitrates, recent acute cardiovascular events or procedures (myocardial infarction, coronary interventions, stroke, etc.), history of other serious cardiovascular events (e.g. arrhythmias, sudden cardiac arrest, congestive heart failure, etc.), systolic blood pressure <90mmHg or diastolic blood pressure <50mmHg at screening
• receiving treatment with cancer chemotherapy