BACKGROUND: Acne and rosacea are common chronic inflammatory skin diseases associated with psychosocial impairment, anxiety, depression, and impaired overall quality of life. Timolol maleate is a potent nonselective β-blocker that causes a combination of vasoconstriction and inhibition of inflammatory mediators. OBJECTIVES: We assessed the clinical efficacy and safety of topical timolol maleate 0.5% for the treatment of acne and rosacea. METHODS: A total of 116 patients (58 patients with rosacea and 58 patients with acne) were treated with topical timolol maleate 0.5% every night before bedtime for eight weeks. RESULTS: The severity of both acne and rosacea decreased relative to baseline; however, the improvement in rosacea was not statistically significant. CONCLUSION: In our study, topical timolol maleate 0.5% demonstrated effectiveness in the treatment of acne, especially in noninflammatory lesions, but seems to be more effective in erythematotelangiectatic rosacea than papulopustular rosacea lesions, with insignificant side effects. The addition of topical timolol to the standard treatment protocol for acne and rosacea is expected to be beneficial, especially by way of improving comedones of acne and resistant inflammatory erythema of both acne and rosacea.