Meibomian gland dysfunction (MGD) is a chronic disease, usually caused by obstruction of the secretory Meibomian glands. The subsequent reduction of gland secretion results in a decreased amount of lipids in the tear film. This results in a faster evaporation of the tear film and thus an evaporative dry eye. MGD alone is responsible for about 60% of all cases in combination with aqueous deficiency for a further 20% of dry eyes. While in Europe up to 20% of the population are suffering from MDD, this is true in Asia for over 60% of the population. MGD is more common in women and it incidence increases with age. It is influenced by the hormonal status as well as chemical and mechanical noxious stimuli. Additional risk factors include various skin diseases such as rosacea, acne or atopy. To diagnose MGD, particular attention should be paid to changes in the lid margin such as plugging or pouting of the ducts, thickening and telangiectasia. However, most important is the diagnostic expression of the glands. At first it should be assessed whether secretion can be caused by pressure to the eyelid against the globe and secondly the quality of the expressed secretions should be evaluated. MGD should be treated according to the severity of the disease. While in mild stages instructions for lid margin hygiene, warming and massage in combination with artificial tears might be sufficient, in more severe stages oral tetracyclin derivatives and anti-inflammatory eye drops such as steroids or CSA are necessary for successful treatment.