The Denmark Strait Overflow Water (DSOW) forms a substantial part of the North Atlantic Deep Water (NADW).In order to permanently monitor the Denmark Strait Overflow (DSO), it has been observed by an array of moored ADCPs and Inverted Echo Sounders (PIESs) directly at the sill since September 1999. The DSOWtransport is derived by three independent methods: First, ADCP measured currents, integrated below the depth of maximum current shear, second, from acoustically determined interface depth and sea surface height, and, third, from the upstream reservoir height, observed by a thermistor chainmooring northeast of the sill. The optimum mooring positions were determined from comparisons with a high resolution model of the Denmark Strait.The first two sets of moorings cover the period from September 1999 to February 2000 and August 2000 to May 2001, thus gaining a DSOW transport time series of more than 14 months. As a result of these observations and model comparisons an average DSOW transport of 2.9 ± 1.0 Sv is calculated. The data confirm earlier short term observations, which showed large fluctuations on time scales of approx. 5 days. Longterm changes of DSOW properties could not be observed during this period yet. The role of hydraulic control in the correlation between reservoir height, observed by the mooring upstream of the sill, and the measured actual transport at the sill is addressed, as well as the correlation between interface depth and sea surface elevation.