Diatoms are photosynthesising algae containing siliceous frustule which are classified under the Bacillariophyceae class. Its existence are everywhere in moist environment such as rivers, ponds, lakes, soils and marine waters. There are nine morphologies of diatoms, namely centric, araphid, symmetrical biraphid, asymmetrical biraphid, nitzschioid, epithemioid, surirelloid, monoraphid and eunotioid. In forensic science, detection of diatoms in tissues may contribute to the diagnosis of drowning. This research aims to identify diatoms based on its morphology in major rivers of Selangor, Malaysia. The samples were collected by scrubbing on the boulders, pebbles and cobbles that were found to be submerged in the rivers and were facing the sunlight using a toothbrush. The rivers involved were Klang, Kemensah, Damansara, Ampang, Kanching and Gombak rivers. The collected samples of diatoms from each river were then heat fixed and observed under microscope. Diatoms were then identified by analysing the morphology of each diatom. Major rivers of Selangor have diatoms which only consisted of eight types of morphology. Diatom of surirelloid morphology was not found in Gombak, Damansara, Kemensah and Klang rivers. Diatoms of eunotioid and asymmetrical biraphid morphology were not found in Damansara and Klang River. Furthermore, diatoms of symmetrical biraphid and araphid were not found in Klang River. Centric diatoms and eunotioid diatoms were not found in Ampang River. Diatoms morphology information will help to narrow down the selection of water bodies of a particular location; linking the suspect as well as the victim. Therefore, this research is vital in forensic science as to provide information and support in the investigation for drowning site.