Chlamydiae are obligate intracellular bacteria causing mucosal infections. The leading agent Chlamydia trachomatis causes three clinical features in eyes: trachoma, neonatal, and adult inclusion conjunctivitis. A rare chlamydial conjunctivitis form called Lymphogranuloma Venereum conjunctivitis can be venereally transmitted. Seldomly Chlamydia psittaci and Chlamydia pneumonia may cause follicular conjunctivitis. Trachoma, the most sight-threatening chlamydial eye infection, lead to approximately 6 million blindness worldwide. Classical trachoma is characterized by chronic follicular keratoconjunctivitis, conjunctival scarring, and pannus formation. According to WHO at least two of the following should be present for clinical trachoma diagnosis: Superior tarsal follicles, limbal follicles or Herbert Pits, typical conjunctival scarring and vascular pannus. These should also be supported by laboratory findings such as organismal isolation and humoral or local antibody detection. The treatment consists of the personal acute sporadic trachoma treatment, the eradication of the disease, and complication management. For acute personnel treatment, systemical and topical forms of Tetracycline, Doxycycline, or Erythromycin are used. For the eradication of the disease, oral Azithromycin is a well-tolerated antibiotic. The management of the complications consists of surgical interventions for scars. In spite of developing hygiene standards and control programs, trachoma is still a major cause of infectious blindness.