Leg swelling is often of edematous nature. The most important differential diagnosis lies in the distinction between venous or lymphatic forms of edema. An increased vascular permeability and alterations in blood composition have also to be taken into account. A particular entity is the lipedema. Next to an accurate history, specific inspection and palpatory criteria permit to distinguish the various forms. Tests for venous function, laboratory and technologically investigative techniques increase diagnostic accuracy. Lymphedema can only be diagnosed by an exact clinical diagnosis.