In a method for integrity monitoring in position determination by means of the Global Positioning System (GPS), especially by means of differential GPS (DGPS) or multi-station DGPS, wherein there is employed a monitor station (M) with a first GPS receiver, provided at a location with a known geographical position, GPS-based position measurement results are transferred on a communication line from the monitor station (M) to a user location (F) the integrity of whose geographical position has to be monitored by means of a second GPS receiver provided at the location (F). A space vector between the location of the monitor station (M) and the location (F) is determined by means of the position measurement results for the location (F) and the monitor station (M), whereupon the degree of agreement is determined between the position for the location (F), the space vector and the known position of the monitor station (M), the degree of agreement being required to correspond to a maximum error in the position for the user location (F).