Mineralogical-petrographical investigation of botoom sediments of basin devoted for fish-culture were perfor- med. Samples of sediments were collected near of the infow of fresh water into the basin (sample no 1), at the centre of basin (sample no 2) and near of outflow of the water from the basin (sample no 3). Additionaly samples were taken from samll vertical profiles in all these three places of sampling. This way in each of sampling points were taken samples a,b,c (from the top of sediments down). The distance between these samples was about 5 cm. Investigations were done with the use of polarizing light microscopy, SEM, EDX as well as ASA methods. Obtained results showed that sediments represnet mudy clays containing admixture of organic matter and secon- darly formed calcite. The main components of sediments are represented by quartz and clay minerals. Sediments contain slightly elevated leval of Zn and Pb as well as orgainc matter aspecially. at the zone of outflow of water from the basin. This may suggests lower leval of oxigen in the water at this part of basin i.e. worse condition for life of fishes.