We evaluated the efficacy and safety of as-needed tadalafil in a diverse clinical population (with varying patient demographics, disease severity, and comorbid medical conditions) of Asian men with erectile dysfunction (ED). An integrated analysis of five double-blind, placebo-controlled trials (N = 1 046) was performed. Patients were randomly assigned to receive 10 mg tadalafil (N = 185), 20 mg tadalafil (N = 510), or placebo (N = 351). Efficacy assessments included the International Index of Erectile Function (IIEF), Sexual Encounter Profile (SEP) diary and Global Assessment Question (GAQ). Patients receiving 10 mg or 20 mg tadalafil showed significant improvement from baseline-to-end point on the Erectile Function domain of the International Index of Erectile Function (IIEF-EF) domain score in all clinical sub-populations analyzed, compared with patients receiving placebo (P < 0.001). The 10-mg and 20-mg tadalafil groups showed a mean success rate of 64.1% and 70.5% for sexual intercourse attempts (SEP3, successful intercourse), respectively, compared with 33.4% in the placebo group (P < 0.001), and 85.5% and 85.4% reported improved erections at end point GAQ, respectively, versus 43.5% in the placebo group (P < 0.001). Tadalafil was well tolerated across all groups studied. Headache and back pain were the most frequently reported adverse events. Overall, tadalafil was effective and well tolerated across a diverse clinical spectrum of Asian men with ED.