The aim of this work is an analysis of ground water quality in the sculptured area of an agricultural catchment. The investigations were performed in 2001-2003 in the catchment of the Ciemięga river in the area of Snopków near Lublin. Ground water samples for the analysis were taken from four sections in two points on each of them: 1 – in cultivation zone at the bottom of a slope under intensive agricultural use, 2 – at the bottom of river valley in a zone of permanent grassland. The analyses revealed high concentrations of biogenic substances (ammonium, nitrate, nitrite, phosphorus and potassium) in the zone of the cultivated field, particularly in vegetation season. At the same time, an evident concentration decrease of most of the biogenic compounds was observed in the zone of grassland, which points to its positive effect on area pollution reduction of agricultural origin in sculptured areas.