An ultrafiltration device and method for the removal of excess fluid in hypervolemic patients and/or removal of toxins in the blood including for patients suffering from either renal or cardiovascular disease is disclosed. An embodiment of the device includes a housing containing multiple large bore hollow fiber membranes which are connected to the patients vascular system via a connecting element comprising bifurcated fluid pathway elements to physiologically channel the blood flow either to or from each hollow fiber membrane of the device, a channel to direct the fluid removed by the device to a suitable collection container or the patients bladder, and controls that control excessive removal of the water from the patient. Devices can be either worn extracorporeally or surgically implanted in order to allow for continuous fluid removal with ambulatory freedom.