To investigate the role of Pythium species associated with root and crown rot in cantaloupe, samples were collected from infected fields in various regions in Kurdistan, Iraq during the 2021 period. Root pieces were washed and cultured on appropriate medium. The Pythium isolates were then purified using the hyphal tip method morphological identified according to the van der Plaats-Niterink mycological key. Identification of this fungus isolates was based on using both morphological characteristics and molecular analysis, on internal tran-scribed spacer (ITS1, ITS4, LSU) are primers that are used for identification. DNA sequences of the fungal pathogen were identified as Pythium hydnosporum a new pathogenic fungi causal agent of cantaloupe vine decline.