The paper presents results of studies on the effects of long-term storage of cattle manure directly on the ground on the contamination of shallow groundwater with dissolved organic carbon (DOC). The research was carried out from January 2008 to December 2009. It was conducted at the site where cattle manure had been stored for about 20 years. Water samples were collected from three wells located at the site of manure storage and next to it. Moreover, at the same time water from two nearby ditches was sampled. Water samples were analyzed calorimetrically for the concentration of DOC using segmented fl ow analysis (S.F.A.S.).  The research indicated that long-term manure storage on the ground resulted in signifi cant pollution of groundwater with dissolved organic carbon. Annual average DOC content in groundwater from the monitored units was approximately from 51.0 to approximately 189.0 mg C dm-3. Its concentration in water samples collected on a monthly basis was as high as 597.0 mg C dm-3.  The concentration of DOC in the surrounding ditches in the study period ranged from 3.5 mg C dm-3 to 12.5 mg C dm-3. Concentration of that element was higher in water from a ditch located in close proximity to manure storage (11.1 mg C dm-3) than in a ditch located further away from that area (6 mg C dm-3).  The research indicates that it is necessary to intensify research towards a better identifi cation of the role of DOC in the movement and accumulation of minerals in the water, and that DOC can be a good indicator of water pollution from agricultural sources..