Background: blepharitis is an inflammatory condition of the eyelid that is usually associated with bacterial infection or some skin conditions (such as dandruff on the scalp, or acne rosacea). Aim of the Work: this study aimedto compare the outcome of using topical azithromycin and conventional therapy in improving signs and symptoms of posterior blepharitis causing dry eye.Patients and Methods: this comparative study was done between usage of conventional therapy and topical azithromycin in treatment of posterior blepharitis causing dry eye. One hundred and twenty eyes of sixty patients of both sexes above age of 18 diagnosed with posterior blepharitis causing dry eye disease are recruited from the ophthalmological clinic of Al-Azhar university Hospitals. Results: the azithromycin group showed a significant improvement of sign, symptoms and investigations over the conventional group in the 2^nd visit (after 1 week) while, there was a non significance regarding the 3^rd visit after one month of treatment and 3^rd after one month of stoppage of treatment. Conclusion: conventional therapy and topical azithromycin are effective on posterior blepharitis causing dry eye disease, azithromycin has more compliance and better tolerability to the patients with sustained effect on the ocular tissue that give it a preference over the conventional therapy.