Fluorescein angiography enables the appropriate qualification of patients for intravitreal injections, and simplifies decisions connected with treatment modifications during the anti-VEGF therapy. The aim of this paper is to present changes of fluorescein angiography images in the course of the anti-VEGF therapy in patients with DME, and in particular those with diffuse macular edema. Conclusions: 1. Persisted leakage in fluorescein angiography images in patients with DME treated with intravitreal anti-VEGF injections may indicate increased risk of recurrence and the need for further treatment. 2. Anti-VEGF therapy proved to be effective not only in patients with diffuse DME but also in other types of macular edema due to diabetic retinopathy. 3. Anti-VEGF monotherapy in DME does not always prevent progress of retinopathy to proliferative stage, and it does not eliminate the need for laser panphotocoagulation when NV develops.