Abstract: A manometer for measuring the hydrodynamic pressure of fluids parenterally administered to a patient. The manometer includes a transparent housing which has a passageway formed in the housing that accommodates continuous flow of fluid therethrough. A pressure measuring chamber is formed in the housing and one end of the pressure measuring chamber is in fluid communication with the passageway. The other end of the pressure measuring chamber communicates with an enclosed air space. The fluid flowing through the passageway enters the pressure measuring chamber and rises to a level which is dependent upon the pressure of the fluid flowing through the passageway. Markings are provided on the housing of the manometer which permit the pressure exerted on the fluid flowing through the passageway to be read directly from the level of the fluid in the pressure measuring chamber.