Human synovial membrane was studied by light- and electronmicroscope and histomorphometrically. Areas of distinct structures are seen. The surface structure fold that is mainly seen in the areaolar and adipose synovial membrane type, seemed to be the prime stucture for the synovial turn over. Villi have fenestrated capillaries and they are covered of A- and AB-synoviocytes. Villi are regarded as the synovia production areas. The fibrous type of the synovial membrane is mostly smooth surfaced and seemed to be an ordinary fibrous connective tissue. The B-synoviocyte is discussed as fibrocyte.