Freshwater mussels are aquatic organisms that are involved in nutrient cycling and water purification. Freshwater mussels have filtering activity and transfer nutrients and energy-rich organic compounds from the water column to the sediments. Besides this activity, freshwater mussels are among the most important water pollution indicators due to their ability to concentrate many environmental contaminants such as heavy metals. The genome of most freshwater mussels has not yet been sequenced. The knowledge about the genome of the freshwater mussel's species can be useful to develop a multi-biomarker panel for early indication of water pollution. This study aimed to sequence the whole genomic DNA of freshwater mussel Unio tumidus using the MinION device. In this study, a total of 6 Gb data and 194 contigs with a total length of 825,486bp were generated while the length of the largest contig was 35,755 and the GC content 37.66% and N50 11647 bp was obtained. The generated data was not enough to assemble the whole genome of the mussels' species, and just a partial sequence could be obtained because of many challenges during the DNA extraction and library preparation. However, to obtain the whole DNA composition of these species making more effort, such as performing more library preparation and sequencing runs, are required, but the finding of this study can be used for the generation of more sequencing data for the assembly of the full genome.