From November 1991 until January 1992, a 956 km2area of the loamy sand to sandy loam region of West‐Flanders (Belgium) was sampled for residual soil nitrate,i.e.the amount of nitrate nitrogen in the soil profile at the end of the growing season. In total, 296 soil samples were taken to a depth of 90 cm (in layers of 30 cm) on arable land only. On basis of the rate of the mineral nitrogen losses occuring during this extended period, all residues present on the date of 21 November 1991 were estimated. This date corresponded with the start of the sampling campaign and is close to the end of the growing season. The residues were lognormally distributed around a mean of 177 kg NO3‐‐N/ha with a minimum of 24 and a maximum of 881 kg NO3‐‐N/ha. Classifying the residues into groups according to the preceding crop, the lowest residues appeared after beets (a median of 59 kg NO3‐‐N/ha). Between cereals, maize, potatoes, and vegetables, no significant differences were found. Each of these four groups had a median residue of about 170 kg NO3‐‐N/ha. The high amounts found after cereals were due to a continuing mineralization of the soil organic matter during the three months between harvest and sampling time. This residual soil mineral nitrogen must be limited to minimize the NO3‐‐N drainage losses during winter which otherwise enhance the nitrate concentration in ground and surface waters.