Background: Although it is important for physicians to have sufficient clinical data on which to base treatment decisions, little comparative data exist regarding newer treatment modalities for rosacea. Objective: The goal of the study was to compare the efficacy and safety of topical azelaic acid 20% cream and topical metronidazole 0.75% cream in the treatment of patients with papulopustular rosacea. Parameters of patient satisfaction to treatment were also assessed. Methods: Forty patients with the clinical manifestation of symmetric facial rosacea were investigated in this single-center, double-blind, randomized, contralateral split-face comparison clinical trial. Results: After 15 weeks of treatment, both azelaic acid and metronidazole induced significant, albeit equal reductions in the number of inflammatory lesions (pustules and papules). A significantly higher physician rating of global improvement was achieved with azelaic acid. Changes in the rosacea signs and symptoms of dryness, burning, telangiectasia, and itching were equal between treatments. A reduction in erythema tended toward significance with azelaic acid at week 15. A trace amount of stinging on application was noted with azelaic acid; however, such discomfort did not appear to concern patients because their overall impression of azelaic acid was superior to that of metronidazole. Conclusion: Azelaic acid 20% cream provides an effective and safe alternative to metro-nidazole 0.75% cream with the added benefit of increased patient satisfaction. (J Am Acad Dermatol 1999;40:961-5.)