Abstarct: Kashkan River, one of the major rivers of Lorestan Province which is considered as an important source of drinking, agricultural, and industrial water supply in the region. The river, flowing from north east to south west, is one of the major tributary of Karkheh River. The present study dealt with assessing of heavy mextal concentration in water and in the surface sediment (from the junction of Madianrood to the junction to Seymareh River). To do so, 15 sediment samples along with 15 water samples were collected in order to determine physico-chemical parameters, anions and cations concentration, and ICP-MS tests. 11 elements, namely iron, aluminum, nickel, copper, lead, cobalt, strontium, selenium, zinc, arsenic, and chromium were selected with regards to the environmental priorities, the amount, and the variation of their concentrations. Generally, the geological formations of the region are classified in three groups: evaporative, carbonate, and terrigenous. Sedimentological studies showed that the sediment texture along the river changes from gravel-sand to muddy-gravel sand. The organic matter increases from upstream toward the downstream and the calcium carbonate in the sediments was affected by Gachsaran Formation. Nickel, iron, cobalt, aluminum, and chromium in the sediments influenced by Kashkan and Amiran formations while strontium and selenium in the sediments were affected by Gachsaran formation, have the highest concentration, and enrichment factor, and probably have geogenic sources. Copper, zinc, lead, and arsenic in the sediments might have geogenic and anthropogenic sources since the highest concentrations of the later were seen in the first station which is under the influence of Afrineh Oil Pump Station and fig farms in Zorantel. The maximum contamination degree was measured in the first station (anthropogenic parameters) and the sixth station (geogenic parameters). The maximum and minimum pollution load index (PLI) in Kashkan River is due to terrigenous and evaporative formations respectively. A comparison of the measured concentration with TEC and PEC showed that the quality of the sediments in third and ninth stations were more concerning in comparison with the other stations. The results of the study of water quality showed that the Kashkan River water quality is mostly affected by evaporative and carbonate formations. The water type of the river is carbonate-calcic and its pH is basic. The river water is over saturated with the dolomite, calcite, aragonite, hematite, and goethite minerals. Aluminum and iron concentrations were higher than WHO 2008 and concentrations of copper, selenium, cobalt, nickel, iron, and strontium were higher the average concentrations of elements in the rivers. The mextal index in most stations was larger than one, which indicated the pollution in these stations.