We assessed the efficacy of topical cyclosporin 0.05% ophthalmic emulsion versus tobramycin 0.3%/dexamethasone 0.1% in patients with posterior blepharitis. Posterior blepharitis improved significantly from the initial study visit with both cyclosporin treatment and tobramycin/dexamethasone. Cyclosporin provided greater improvements in Schirmer's scores (P < 0.001) and tear break-up time (P = 0.018) than tobramycin/dexamethasone after 12 weeks of treatment. Eyelid health also improved in both groups, but the mean improvement in meibomian gland secretion quality was significantly greater with cyclosporin than with tobramycin/dexamethasone (P = 0.015). Moreover, a higher percentage of patients in the cyclosporin treatment group had improvements in symptoms of blurred vision, burning, and itching and more cyclosporin-treated patients experienced resolution of lid telangiectasia. The findings in this prospective study suggest that posterior blepharitis can be more effectively treated with cyclosporin than with tobramycin/dexamethasone. These findings should be further evaluated in large-scale, controlled, clinical trials.